- simplify multicast client flow control, base all on ACKs
[oweals/gnunet.git] / src / mesh / gnunet-service-mesh.c
index 933ce492a9f0a8d817e8677bfdd4ca497f4e0e9e..a294bbd398a7443380a2971192a36b8544e25079 100644 (file)
@@ -42,6 +42,7 @@
  * - relay corking down to core
  * - set ttl relative to tree depth
  * - Add data ACK count in path ACK
+ * - Make common GNUNET_MESH_Data header for unicast, to_orig, multicast
  * TODO END
  */
 
@@ -114,12 +115,8 @@ struct MeshData
   /** Tunnel it belongs to. */
   struct MeshTunnel *t;
 
-  /** In case of a multicast, task to allow a client to send more data if
-   * some neighbor is too slow. */
-  GNUNET_SCHEDULER_TaskIdentifier *task;
-
   /** How many remaining neighbors we need to send this to. */
-  unsigned int *reference_counter;
+  unsigned int reference_counter;
 
   /** Size of the data. */
   size_t data_len;
@@ -511,6 +508,22 @@ struct MeshTunnelChildInfo
      * Last ACK sent to that child (BCK ACK).
      */
   uint32_t bck_ack;
+
+    /**
+     * Circular buffer pointing to MeshPeerQueue elements.
+     * Size determined by the tunnel queue size.
+     */
+  struct MeshPeerQueue **send_buffer;
+
+    /**
+     * Index of the oldest element in the send_buffer.
+     */
+  unsigned int send_buffer_start;
+
+    /**
+     * How many elements are already in the buffer.
+     */
+  unsigned int send_buffer_n;
 };
 
 
@@ -779,6 +792,9 @@ mesh_debug (void *cls, int success)
 }
 #endif
 
+unsigned int debug_fwd_ack;
+unsigned int debug_bck_ack;
+
 #endif
 
 /******************************************************************************/
@@ -1147,6 +1163,7 @@ static void
 queue_add (void *cls, uint16_t type, size_t size,
            struct MeshPeerInfo *dst, struct MeshTunnel *t);
 
+
 /**
  * Free a transmission that was already queued with all resources
  * associated to the request.
@@ -1157,6 +1174,34 @@ queue_add (void *cls, uint16_t type, size_t size,
 static void
 queue_destroy (struct MeshPeerQueue *queue, int clear_cls);
 
+
+/**
+ * @brief Get the next transmittable message from the queue.
+ *
+ * This will be the head, except in the case of being a data packet
+ * not allowed by the destination peer.
+ *
+ * @param peer Destination peer.
+ *
+ * @return The next viable MeshPeerQueue element to send to that peer.
+ *         NULL when there are no transmittable messages.
+ */
+struct MeshPeerQueue *
+queue_get_next (const struct MeshPeerInfo *peer);
+
+
+/**
+ * Core callback to write a queued packet to core buffer
+ *
+ * @param cls Closure (peer info).
+ * @param size Number of bytes available in buf.
+ * @param buf Where the to write the message.
+ *
+ * @return number of bytes written to buf
+ */
+static size_t
+queue_send (void *cls, size_t size, void *buf);
+
 /******************************************************************************/
 /************************         ITERATORS        ****************************/
 /******************************************************************************/
@@ -1586,6 +1631,7 @@ announce_application (void *cls, const struct GNUNET_HashCode * key, void *value
 
   block.id = my_full_id;
   c =  GNUNET_CONTAINER_multihashmap_get (applications, key);
+  GNUNET_assert(NULL != c);
   block.type = (long) GNUNET_CONTAINER_multihashmap_get (c->apps, key);
   if (0 == block.type)
   {
@@ -1724,23 +1770,9 @@ announce_id (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 static void
 data_descriptor_decrement_rc (struct MeshData *mesh_data)
 {
-  /* Make sure it's a multicast packet */
-  GNUNET_assert (NULL != mesh_data->reference_counter);
-
-  if (0 == --(*(mesh_data->reference_counter)))
+  if (0 == --(mesh_data->reference_counter))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Last copy!\n");
-    if (NULL != mesh_data->task)
-    {
-      if (GNUNET_SCHEDULER_NO_TASK != *(mesh_data->task))
-      {
-        GNUNET_SCHEDULER_cancel (*(mesh_data->task));
-        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " notifying client...\n");
-        GNUNET_SERVER_receive_done (mesh_data->t->owner->handle, GNUNET_OK);
-      }
-      GNUNET_free (mesh_data->task);
-    }
-    GNUNET_free (mesh_data->reference_counter);
     GNUNET_free (mesh_data->data);
     GNUNET_free (mesh_data);
   }
@@ -1796,32 +1828,6 @@ client_is_subscribed (uint16_t message_type, struct MeshClient *c)
 }
 
 
-/**
- * Allow a client to send more data after transmitting a multicast message
- * which some neighbor has not yet accepted altough a reasonable time has
- * passed.
- *
- * @param cls Closure (DataDescriptor containing the task identifier)
- * @param tc Task Context
- * 
- * FIXME reference counter cshould be just int
- */
-static void
-client_allow_send (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
-  struct MeshData *mdata = cls;
-
-  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
-    return;
-  GNUNET_assert (NULL != mdata->reference_counter);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "CLIENT ALLOW SEND DESPITE %u COPIES PENDING\n",
-              *(mdata->reference_counter));
-  *(mdata->task) = GNUNET_SCHEDULER_NO_TASK;
-  GNUNET_SERVER_receive_done (mdata->t->owner->handle, GNUNET_OK);
-}
-
-
 /**
  * Check whether client wants traffic from a tunnel.
  *
@@ -2254,8 +2260,7 @@ send_message (const struct GNUNET_MessageHeader *message,
     m->ttl = htonl (ntohl (m->ttl) - 1);
   }
   info->mesh_data->data_len = size;
-  info->mesh_data->reference_counter = GNUNET_malloc (sizeof (unsigned int));
-  *info->mesh_data->reference_counter = 1;
+  info->mesh_data->reference_counter = 1;
   neighbor = peer_info_get (peer);
   for (p = neighbor->path_head; NULL != p; p = p->next)
   {
@@ -3031,7 +3036,22 @@ tunnel_destroy_child (void *cls,
                       const struct GNUNET_HashCode * key,
                       void *value)
 {
-  GNUNET_free (value);
+  struct MeshTunnelChildInfo *cinfo = value;
+  struct MeshTunnel *t = cls;
+  unsigned int c;
+  unsigned int i;
+
+  for (c = 0; c < cinfo->send_buffer_n; c++)
+  {
+    i = (cinfo->send_buffer_start + c) % t->fwd_queue_max;
+    if (NULL != cinfo->send_buffer[i])
+      queue_destroy(cinfo->send_buffer[i], GNUNET_YES);
+    else
+      GNUNET_break (0);
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO, "%u %u\n", c, cinfo->send_buffer_n);
+  }
+  GNUNET_free_non_null (cinfo->send_buffer);
+  GNUNET_free (cinfo);
   return GNUNET_YES;
 }
 
@@ -3166,7 +3186,7 @@ tunnel_add_client (struct MeshTunnel *t, struct MeshClient *c)
 
   GNUNET_array_append (t->clients, t->nclients, c);
   clinfo.fwd_ack = t->fwd_pid + 1;
-  clinfo.bck_ack = t->nobuffer ? 1 : INITIAL_WINDOW_SIZE;
+  clinfo.bck_ack = t->nobuffer ? 1 : INITIAL_WINDOW_SIZE - 1;
   clinfo.fwd_pid = t->fwd_pid;
   clinfo.bck_pid = (uint32_t) -1; // Expected next: 0
   t->nclients--;
@@ -3239,7 +3259,7 @@ tunnel_send_multicast_iterator (void *cls, GNUNET_PEER_Id neighbor_id)
   info = GNUNET_malloc (sizeof (struct MeshTransmissionDescriptor));
 
   info->mesh_data = mdata;
-  (*(mdata->reference_counter)) ++;
+  (mdata->reference_counter) ++;
   info->destination = neighbor_id;
   GNUNET_PEER_resolve (neighbor_id, &neighbor);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "   sending to %s...\n",
@@ -3255,12 +3275,14 @@ tunnel_send_multicast_iterator (void *cls, GNUNET_PEER_Id neighbor_id)
 
 
 /**
- * Send a message in a tunnel in multicast, sending a copy to each child node
+ * Queue a message in a tunnel in multicast, sending a copy to each child node
  * down the local one in the tunnel tree.
  *
  * @param t Tunnel in which to send the data.
  * @param msg Message to be sent.
- * @param internal Has the service generated this message?
+ * @param internal DEPRECATED Has the service generated this message?
+ * 
+ * FIXME remove internal if no use comes up
  */
 static void
 tunnel_send_multicast (struct MeshTunnel *t,
@@ -3271,9 +3293,9 @@ tunnel_send_multicast (struct MeshTunnel *t,
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               " sending a multicast packet...\n");
+
   mdata = GNUNET_malloc (sizeof (struct MeshData));
   mdata->data_len = ntohs (msg->size);
-  mdata->reference_counter = GNUNET_malloc (sizeof (unsigned int));
   mdata->t = t;
   mdata->data = GNUNET_malloc (mdata->data_len);
   memcpy (mdata->data, msg, mdata->data_len);
@@ -3282,6 +3304,21 @@ tunnel_send_multicast (struct MeshTunnel *t,
     struct GNUNET_MESH_Multicast *mcast;
 
     mcast = (struct GNUNET_MESH_Multicast *) mdata->data;
+    if (t->fwd_queue_n >= t->fwd_queue_max)
+    {
+      GNUNET_break (0);
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "  queue full!\n");
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "  message from %s!\n",
+                  GNUNET_i2s(&mcast->oid));
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "  message at %s!\n",
+                  GNUNET_i2s(&my_full_id));
+      GNUNET_free (mdata->data);
+      GNUNET_free (mdata);
+      return;
+    }
+    t->fwd_queue_n++;
     mcast->ttl = htonl (ntohl (mcast->ttl) - 1);
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  data packet, ttl: %u\n",
                 ntohl (mcast->ttl));
@@ -3290,30 +3327,15 @@ tunnel_send_multicast (struct MeshTunnel *t,
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  not a data packet, no ttl\n");
   }
-  if (NULL != t->owner && GNUNET_YES != t->owner->shutting_down
-      && GNUNET_NO == internal)
-  {
-    mdata->task = GNUNET_malloc (sizeof (GNUNET_SCHEDULER_TaskIdentifier));
-    (*(mdata->task)) =
-        GNUNET_SCHEDULER_add_delayed (unacknowledged_wait_time, &client_allow_send,
-                                      mdata);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "timeout task %u\n",
-                *(mdata->task));
-  }
 
   tree_iterate_children (t->tree, &tunnel_send_multicast_iterator, mdata);
-  if (*(mdata->reference_counter) == 0)
+  if (mdata->reference_counter == 0)
   {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "  no one to send data to\n");
     GNUNET_free (mdata->data);
-    GNUNET_free (mdata->reference_counter);
-    if (NULL != mdata->task)
-    {
-      GNUNET_SCHEDULER_cancel(*(mdata->task));
-      GNUNET_free (mdata->task);
-      GNUNET_SERVER_receive_done (t->owner->handle, GNUNET_OK);
-    }
-    // FIXME change order?
     GNUNET_free (mdata);
+    t->fwd_queue_n--;
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               " sending a multicast packet done\n");
@@ -3378,10 +3400,13 @@ tunnel_get_neighbor_fc (const struct MeshTunnel *t,
     cinfo->id = GNUNET_PEER_intern (peer);
     cinfo->skip = t->fwd_pid;
 
-    delta = t->nobuffer ? 1 : INITIAL_WINDOW_SIZE;
+    delta = t->nobuffer ? 1 : INITIAL_WINDOW_SIZE - 1;
     cinfo->fwd_ack = t->fwd_pid + delta;
     cinfo->bck_ack = delta;
 
+    cinfo->send_buffer =
+        GNUNET_malloc (sizeof(struct MeshPeerQueue *) * t->fwd_queue_max);
+
     GNUNET_assert (GNUNET_OK ==
       GNUNET_CONTAINER_multihashmap_put (t->children_fc,
                                          &peer->hashPubKey,
@@ -3463,7 +3488,7 @@ tunnel_get_child_fwd_ack (void *cls,
  *
  * @param t Tunnel.
  *
- * @return Maximum PID allowed (uint32 MAX), -1 if node has no children.
+ * @return Maximum PID allowed (uint32 MAX), -1LL if node has no children.
  */
 static int64_t
 tunnel_get_children_fwd_ack (struct MeshTunnel *t)
@@ -3520,7 +3545,7 @@ tunnel_set_client_fwd_ack (struct MeshTunnel *t,
  * @param t Tunnel on which to look.
  * 
  * @return Corresponding ACK value (max uint32_t).
- *         If no clients are suscribed, -1.
+ *         If no clients are suscribed, -1LL.
  */
 static int64_t
 tunnel_get_clients_fwd_ack (struct MeshTunnel *t)
@@ -3535,9 +3560,9 @@ tunnel_get_clients_fwd_ack (struct MeshTunnel *t)
     return -1LL;
   }
 
-  for (ack = -1, i = 0; i < t->nclients; i++)
+  for (ack = -1LL, i = 0; i < t->nclients; i++)
   {
-    if (-1 == ack ||
+    if (-1LL == ack ||
         (GNUNET_YES == t->speed_min &&
          GNUNET_YES == GMC_is_pid_bigger (ack, t->clients_fc[i].fwd_ack)) ||
         (GNUNET_NO == t->speed_min &&
@@ -3565,24 +3590,27 @@ tunnel_get_clients_fwd_ack (struct MeshTunnel *t)
 static uint32_t
 tunnel_get_fwd_ack (struct MeshTunnel *t)
 {
+  uint32_t ack;
   uint32_t count;
   uint32_t buffer_free;
   int64_t child_ack;
   int64_t client_ack;
-  uint32_t ack;
 
   count = t->fwd_pid - t->skip;
   buffer_free = t->fwd_queue_max - t->fwd_queue_n;
   ack = count + buffer_free; // Might overflow 32 bits, it's ok!
   child_ack = tunnel_get_children_fwd_ack (t);
   client_ack = tunnel_get_clients_fwd_ack (t);
-  if (-1 == child_ack)
+  if (-1LL == child_ack)
   {
     // Node has no children, child_ack AND core buffer are irrelevant.
-    GNUNET_break (-1 != client_ack); // No children AND no clients? Not good! // FIXME fc
+    GNUNET_break (-1LL != client_ack); // No children AND no clients? Not good!
     return (uint32_t) client_ack;
   }
-
+  if (-1LL == client_ack)
+  {
+    client_ack = ack;
+  }
   if (GNUNET_YES == t->speed_min)
   {
     ack = GMC_min_pid ((uint32_t) child_ack, ack);
@@ -3595,7 +3623,8 @@ tunnel_get_fwd_ack (struct MeshTunnel *t)
   }
   if (GNUNET_YES == t->nobuffer && GMC_is_pid_bigger(ack, t->fwd_pid))
     ack = t->fwd_pid + 1; // Might overflow 32 bits, it's ok!
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "c %u, bf %u, ch %u, cl %u, ACK: %u\n",
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "c %u, bf %u, ch %lld, cl %lld, ACK: %u\n",
               count, buffer_free, child_ack, client_ack, ack);
   return ack;
 }
@@ -3706,11 +3735,6 @@ tunnel_send_fwd_ack (struct MeshTunnel *t, uint16_t type)
         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Not sending ACK, nobuffer\n");
         return;
       }
-      if (t->fwd_queue_max > t->fwd_queue_n * 2)
-      {
-        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Not sending ACK, buffer free\n");
-        return;
-      }
       break;
     case GNUNET_MESSAGE_TYPE_MESH_ACK:
     case GNUNET_MESSAGE_TYPE_MESH_LOCAL_ACK:
@@ -3719,6 +3743,20 @@ tunnel_send_fwd_ack (struct MeshTunnel *t, uint16_t type)
       GNUNET_break (0);
   }
 
+  /* Check if we need no retransmit the ACK */
+  if (t->fwd_queue_max > t->fwd_queue_n * 2 &&
+      GMC_is_pid_bigger(t->last_fwd_ack, t->fwd_pid))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Not sending ACK, buffer free\n");
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "  t->qmax: %u, t->qn: %u\n",
+                t->fwd_queue_max, t->fwd_queue_n);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "  t->pid: %u, t->ack: %u\n",
+                t->fwd_pid, t->last_fwd_ack);
+    return;
+  }
+
   /* Ok, ACK might be necessary, what PID to ACK? */
   ack = tunnel_get_fwd_ack (t);
 
@@ -3732,6 +3770,7 @@ tunnel_send_fwd_ack (struct MeshTunnel *t, uint16_t type)
   t->last_fwd_ack = ack;
   GNUNET_PEER_resolve (tree_get_predecessor (t->tree), &id);
   send_ack (t, &id, ack);
+  debug_fwd_ack++;
 }
 
 
@@ -3848,6 +3887,89 @@ tunnel_send_bck_ack (struct MeshTunnel *t, uint16_t type)
 }
 
 
+/**
+ * @brief Re-initiate traffic to this peer if necessary.
+ *
+ * Check if there is traffic queued towards this peer
+ * and the core transmit handle is NULL (traffic was stalled).
+ * If so, call core tmt rdy.
+ *
+ * @param cls Closure (unused)
+ * @param peer_id Short ID of peer to which initiate traffic.
+ */
+static void
+peer_unlock_queue(void *cls, GNUNET_PEER_Id peer_id)
+{
+  struct MeshPeerInfo *peer;
+  struct GNUNET_PeerIdentity id;
+  struct MeshPeerQueue *q;
+  size_t size;
+
+  peer = peer_info_get_short(peer_id);
+  if (NULL != peer->core_transmit)
+    return;
+
+  q = queue_get_next(peer);
+  if (NULL == q)
+  {
+    /* Might br multicast traffic already sent to this particular peer but
+     * not to other children in this tunnel.
+     * This way t->queue_n would be > 0 but the queue of this particular peer
+     * would be empty.
+     */
+    return;
+  }
+  size = q->size;
+  GNUNET_PEER_resolve (peer->id, &id);
+  peer->core_transmit =
+        GNUNET_CORE_notify_transmit_ready(core_handle,
+                                          0,
+                                          0,
+                                          GNUNET_TIME_UNIT_FOREVER_REL,
+                                          &id,
+                                          size,
+                                          &queue_send,
+                                          peer);
+        return;
+}
+
+
+/**
+ * @brief Allow transmission of FWD traffic on this tunnel
+ *
+ * Check if there is traffic queued towards any children
+ * and the core transmit handle is NULL, and if so, call core tmt rdy.
+ *
+ * @param t Tunnel on which to unlock FWD traffic.
+ */
+static void
+tunnel_unlock_fwd_queues (struct MeshTunnel *t)
+{
+  if (0 == t->fwd_queue_n)
+    return;
+
+  tree_iterate_children (t->tree, &peer_unlock_queue, NULL);
+}
+
+
+/**
+ * @brief Allow transmission of BCK traffic on this tunnel
+ *
+ * Check if there is traffic queued towards the root of the tree
+ * and the core transmit handle is NULL, and if so, call core tmt rdy.
+ *
+ * @param t Tunnel on which to unlock BCK traffic.
+ */
+static void
+tunnel_unlock_bck_queue (struct MeshTunnel *t)
+{
+  if (0 == t->bck_queue_n)
+    return;
+
+  peer_unlock_queue(NULL, tree_get_predecessor(t->tree));
+}
+
+
 /**
  * Send a message to all peers in this tunnel that the tunnel is no longer
  * valid.
@@ -3887,6 +4009,13 @@ tunnel_cancel_queues (void *cls, GNUNET_PEER_Id neighbor_id)
     next = pq->next;
     if (pq->tunnel == t)
     {
+      if (GNUNET_MESSAGE_TYPE_MESH_MULTICAST == pq->type ||
+          GNUNET_MESSAGE_TYPE_MESH_UNICAST == pq->type ||
+          GNUNET_MESSAGE_TYPE_MESH_TO_ORIGIN == pq->type)
+      {
+        // Should have been removed on destroy children
+        GNUNET_break (0);
+      }
       queue_destroy (pq, GNUNET_YES);
     }
   }
@@ -3915,8 +4044,6 @@ tunnel_destroy (struct MeshTunnel *t)
   if (NULL == t)
     return GNUNET_OK;
 
-  tree_iterate_children (t->tree, &tunnel_cancel_queues, t);
-
   r = GNUNET_OK;
   c = t->owner;
 #if MESH_DEBUG
@@ -3984,6 +4111,8 @@ tunnel_destroy (struct MeshTunnel *t)
                                          t);
   GNUNET_CONTAINER_multihashmap_destroy (t->children_fc);
 
+  tree_iterate_children (t->tree, &tunnel_cancel_queues, t);
+
   tree_destroy (t->tree);
 
   if (NULL != t->regex_ctx)
@@ -4198,8 +4327,9 @@ send_core_path_create (void *cls, size_t size, void *buf)
   msg->header.type = htons (GNUNET_MESSAGE_TYPE_MESH_PATH_CREATE);
   msg->tid = ntohl (t->id.tid);
 
+  opt = 0;
   if (GNUNET_YES == t->speed_min)
-    opt = MESH_TUNNEL_OPT_SPEED_MIN;
+    opt |= MESH_TUNNEL_OPT_SPEED_MIN;
   if (GNUNET_YES == t->nobuffer)
     opt |= MESH_TUNNEL_OPT_NOBUFFER;
   msg->opt = htonl(opt);
@@ -4343,7 +4473,9 @@ queue_destroy (struct MeshPeerQueue *queue, int clear_cls)
         break;
     default:
         GNUNET_break (0);
-        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "   type unknown!\n");
+        GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                    "   type %u unknown!\n",
+                    queue->type);
     }
     GNUNET_free_non_null (queue->cls);
   }
@@ -4357,7 +4489,7 @@ queue_destroy (struct MeshPeerQueue *queue, int clear_cls)
 /**
  * @brief Get the next transmittable message from the queue.
  *
- * This will be the head, expect in the case of being a data packet
+ * This will be the head, except in the case of being a data packet
  * not allowed by the destination peer.
  *
  * @param peer Destination peer.
@@ -4366,29 +4498,75 @@ queue_destroy (struct MeshPeerQueue *queue, int clear_cls)
  *         NULL when there are no transmittable messages.
  */
 struct MeshPeerQueue *
-queue_get_next (static struct MeshPeerInfo *peer)
+queue_get_next (const struct MeshPeerInfo *peer)
 {
   struct MeshPeerQueue *q;
   struct MeshTunnel *t;
   struct MeshTransmissionDescriptor *info;
+  struct MeshTunnelChildInfo *cinfo;
+  struct GNUNET_MESH_Unicast *ucast;
+  struct GNUNET_MESH_ToOrigin *to_orig;
+  struct GNUNET_MESH_Multicast *mcast;
+  struct GNUNET_PeerIdentity id;
+  uint32_t pid;
+  uint32_t ack;
 
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "*********   selecting message\n");
   for (q = peer->queue_head; NULL != q; q = q->next)
   {
     t = q->tunnel;
+    info = q->cls;
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "*********     %s\n",
+                GNUNET_MESH_DEBUG_M2S(q->type));
     switch (q->type)
     {
       case GNUNET_MESSAGE_TYPE_MESH_UNICAST:
-        info = q->cls;
+        ucast = (struct GNUNET_MESH_Unicast *) info->mesh_data->data;
+        pid = ntohl (ucast->pid);
+        GNUNET_PEER_resolve (info->peer->id, &id);
+        cinfo = tunnel_get_neighbor_fc(t, &id);
+        ack = cinfo->fwd_ack;
         break;
       case GNUNET_MESSAGE_TYPE_MESH_TO_ORIGIN:
+        to_orig = (struct GNUNET_MESH_ToOrigin *) info->mesh_data->data;
+        pid = ntohl (to_orig->pid);
+        ack = t->bck_ack;
         break;
       case GNUNET_MESSAGE_TYPE_MESH_MULTICAST:
+        mcast = (struct GNUNET_MESH_Multicast *) info->mesh_data->data;
+        if (GNUNET_MESSAGE_TYPE_MESH_MULTICAST != ntohs(mcast->header.type)) 
+        {
+          // Not a multicast payload: multicast control traffic (destroy, etc)
+          return q;
+        }
+        pid = ntohl (mcast->pid);
+        GNUNET_PEER_resolve (info->peer->id, &id);
+        cinfo = tunnel_get_neighbor_fc(t, &id);
+        ack = cinfo->fwd_ack;
         break;
       default:
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "*********   OK!\n");
         return q;
+    }
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "*********     ACK: %u, PID: %u\n",
+                    ack, pid);
+    if (GNUNET_NO == GMC_is_pid_bigger(pid, ack))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "*********   OK!\n");
+      return q;
+    }
+    else
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "*********     NEXT!\n");
     }
   }
-  // FIXME fc WIP
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "*********   nothing found\n");
   return NULL;
 }
 
@@ -4409,33 +4587,39 @@ queue_send (void *cls, size_t size, void *buf)
     struct GNUNET_MessageHeader *msg;
     struct MeshPeerQueue *queue;
     struct MeshTunnel *t;
+    struct MeshTunnelChildInfo *cinfo;
+    struct GNUNET_PeerIdentity dst_id;
     size_t data_size;
 
     peer->core_transmit = NULL;
-    queue = peer->queue_head;
-
+    
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "********* Queue send\n");
+    queue = queue_get_next(peer);
 
-    /* If queue is empty, send should have been cancelled */
+    /* Queue has no internal mesh traffic not sendable payload */
     if (NULL == queue)
     {
-        GNUNET_break(0);
-        return 0;
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "*********   not ready, return\n");
+      if (NULL == peer->queue_head)
+        GNUNET_break(0); // Should've been canceled
+      return 0;
     }
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "*********   not empty\n");
 
+    GNUNET_PEER_resolve (peer->id, &dst_id);
     /* Check if buffer size is enough for the message */
     if (queue->size > size)
     {
-        struct GNUNET_PeerIdentity id;
 
-        GNUNET_PEER_resolve (peer->id, &id);
+
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "*********   not enough room, reissue\n");
         peer->core_transmit =
             GNUNET_CORE_notify_transmit_ready(core_handle,
                                               0,
                                               0,
                                               GNUNET_TIME_UNIT_FOREVER_REL,
-                                              &id,
+                                              &dst_id,
                                               queue->size,
                                               &queue_send,
                                               peer);
@@ -4448,8 +4632,8 @@ queue_send (void *cls, size_t size, void *buf)
     {
       t->fwd_queue_n--;
       GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                  "*********   unicast: %u\n",
-                  t->fwd_queue_n);
+                  "*********   unicast: t->q (%u/%u)\n",
+                  t->fwd_queue_n, t->fwd_queue_max);
     }
     else if (GNUNET_MESSAGE_TYPE_MESH_TO_ORIGIN == queue->type)
     {
@@ -4465,8 +4649,8 @@ queue_send (void *cls, size_t size, void *buf)
       case GNUNET_MESSAGE_TYPE_MESH_PATH_BROKEN:
       case GNUNET_MESSAGE_TYPE_MESH_PATH_DESTROY:
         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                    "*********   raw: %u\n",
-                    queue->type);
+                    "*********   raw: %s\n",
+                    GNUNET_MESH_DEBUG_M2S (queue->type));
         /* Fall through */
       case GNUNET_MESSAGE_TYPE_MESH_UNICAST:
       case GNUNET_MESSAGE_TYPE_MESH_TO_ORIGIN:
@@ -4486,6 +4670,12 @@ queue_send (void *cls, size_t size, void *buf)
         break;
       case GNUNET_MESSAGE_TYPE_MESH_MULTICAST:
         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "*********   multicast\n");
+        {
+          struct MeshTransmissionDescriptor *info = queue->cls;
+          if (info->mesh_data->reference_counter == 1)
+            t->fwd_queue_n--;
+          // FIXME fc (t->fwd_queue_n--)
+        }
         data_size = send_core_data_multicast(queue->cls, size, buf);
         tunnel_send_fwd_ack (t, GNUNET_MESSAGE_TYPE_MESH_MULTICAST);
         break;
@@ -4504,6 +4694,30 @@ queue_send (void *cls, size_t size, void *buf)
                     queue->type);
         data_size = 0;
     }
+    switch (queue->type)
+    {
+      case GNUNET_MESSAGE_TYPE_MESH_UNICAST:
+      case GNUNET_MESSAGE_TYPE_MESH_TO_ORIGIN:
+      case GNUNET_MESSAGE_TYPE_MESH_MULTICAST:
+        cinfo = tunnel_get_neighbor_fc(t, &dst_id);
+        if (cinfo->send_buffer[cinfo->send_buffer_start] != queue)
+        {
+          GNUNET_break(0);
+          GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                      "at pos %u (%p) != %p\n",
+                      cinfo->send_buffer_start,
+                      cinfo->send_buffer[cinfo->send_buffer_start],
+                      queue);
+        }
+        GNUNET_break(cinfo->send_buffer_n > 0);
+        cinfo->send_buffer[cinfo->send_buffer_start] = NULL;
+        cinfo->send_buffer_n--;
+        cinfo->send_buffer_start++;
+        cinfo->send_buffer_start %= t->fwd_queue_max;
+        break;
+      default:
+        break;
+    }
 
     /* Free queue, but cls was freed by send_core_* */
     queue_destroy (queue, GNUNET_NO);
@@ -4515,7 +4729,8 @@ queue_send (void *cls, size_t size, void *buf)
     }
 
     /* If more data in queue, send next */
-    if (NULL != peer->queue_head)
+    queue = queue_get_next(peer);
+    if (NULL != queue)
     {
         struct GNUNET_PeerIdentity id;
 
@@ -4527,10 +4742,17 @@ queue_send (void *cls, size_t size, void *buf)
                                               0,
                                               GNUNET_TIME_UNIT_FOREVER_REL,
                                               &id,
-                                              peer->queue_head->size,
+                                              queue->size,
                                               &queue_send,
                                               peer);
     }
+    else
+    {
+      if (NULL != peer->queue_head)
+        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                    "*********   %s stalled\n",
+                    GNUNET_i2s(&my_full_id));
+    }
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "*********   return %d\n", data_size);
     return data_size;
 }
@@ -4550,8 +4772,11 @@ queue_add (void *cls, uint16_t type, size_t size,
            struct MeshPeerInfo *dst, struct MeshTunnel *t)
 {
   struct MeshPeerQueue *queue;
+  struct MeshTunnelChildInfo *cinfo;
+  struct GNUNET_PeerIdentity id;
   unsigned int *max;
   unsigned int *n;
+  unsigned int i;
 
   n = NULL;
   if (GNUNET_MESSAGE_TYPE_MESH_UNICAST == type ||
@@ -4572,6 +4797,8 @@ queue_add (void *cls, uint16_t type, size_t size,
         GNUNET_break_op(0);       // TODO: kill connection?
       else
         GNUNET_break(0);
+      GNUNET_STATISTICS_update(stats, "# messages dropped (buffer full)",
+                               1, GNUNET_NO);
       return;                       // Drop message
     }
     (*n)++;
@@ -4583,11 +4810,9 @@ queue_add (void *cls, uint16_t type, size_t size,
   queue->peer = dst;
   queue->tunnel = t;
   GNUNET_CONTAINER_DLL_insert_tail (dst->queue_head, dst->queue_tail, queue);
+  GNUNET_PEER_resolve (dst->id, &id);
   if (NULL == dst->core_transmit)
   {
-      struct GNUNET_PeerIdentity id;
-
-      GNUNET_PEER_resolve (dst->id, &id);
       dst->core_transmit =
           GNUNET_CORE_notify_transmit_ready(core_handle,
                                             0,
@@ -4598,6 +4823,27 @@ queue_add (void *cls, uint16_t type, size_t size,
                                             &queue_send,
                                             dst);
   }
+  if (NULL == n) // Is this internal mesh traffic?
+    return;
+
+  // It's payload, keep track of buffer per peer.
+  cinfo = tunnel_get_neighbor_fc(t, &id);
+  i = (cinfo->send_buffer_start + cinfo->send_buffer_n) % t->fwd_queue_max;
+  if (NULL != cinfo->send_buffer[i])
+  {
+    GNUNET_break (cinfo->send_buffer_n == t->fwd_queue_max); // aka i == start
+    queue_destroy(cinfo->send_buffer[cinfo->send_buffer_start], GNUNET_YES);
+    cinfo->send_buffer_start++;
+    cinfo->send_buffer_start %= t->fwd_queue_max;
+    cinfo->send_buffer_n--;
+  }
+  cinfo->send_buffer[i] = queue;
+  cinfo->send_buffer_n++;
+  if (cinfo->send_buffer_n > t->fwd_queue_max)
+  {
+    GNUNET_break (0);
+    cinfo->send_buffer_n = t->fwd_queue_max;
+  }
 }
 
 
@@ -4682,6 +4928,9 @@ handle_mesh_path_create (void *cls, const struct GNUNET_PeerIdentity *peer,
                    GNUNET_YES : GNUNET_NO;
     t->nobuffer = (0 != (opt & MESH_TUNNEL_OPT_NOBUFFER)) ?
                   GNUNET_YES : GNUNET_NO;
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "  speed_min: %d, nobuffer:%d\n",
+                t->speed_min, t->nobuffer);
 
     if (GNUNET_YES == t->nobuffer)
     {
@@ -5285,8 +5534,7 @@ handle_mesh_ack (void *cls, const struct GNUNET_PeerIdentity *peer,
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Got an ACK packet from %s!\n",
               GNUNET_i2s (peer));
   msg = (struct GNUNET_MESH_ACK *) message;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, " of type %s\n",
-              GNUNET_MESH_DEBUG_M2S (ntohs (msg[1].header.type)));
+
   t = tunnel_get (&msg->oid, ntohl (msg->tid));
 
   if (NULL == t)
@@ -5299,22 +5547,24 @@ handle_mesh_ack (void *cls, const struct GNUNET_PeerIdentity *peer,
   ack = ntohl (msg->pid);
 
   /* Is this a forward or backward ACK? */
-  if (tree_get_predecessor(t->tree) == GNUNET_PEER_search(peer))
+  if (tree_get_predecessor(t->tree) != GNUNET_PEER_search(peer))
   {
     struct MeshTunnelChildInfo *cinfo;
 
+    debug_bck_ack++;
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  FWD ACK\n");
     cinfo = tunnel_get_neighbor_fc (t, peer);
     cinfo->fwd_ack = ack;
     tunnel_send_fwd_ack (t, GNUNET_MESSAGE_TYPE_MESH_ACK);
+    tunnel_unlock_fwd_queues (t);
   }
   else
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "  BCK ACK\n");
     t->bck_ack = ack;
     tunnel_send_bck_ack (t, GNUNET_MESSAGE_TYPE_MESH_ACK);
+    tunnel_unlock_bck_queue (t);
   }
-  // FIXME fc Unlock queues?
   return GNUNET_OK;
 }
 
@@ -5536,6 +5786,7 @@ path_refresh (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   msg = (struct GNUNET_MESH_Multicast *) cbuf;
   msg->header.size = htons (size);
   msg->header.type = htons (GNUNET_MESSAGE_TYPE_MESH_MULTICAST);
+  // FIXME: change type to != MULTICAST
   msg->oid = my_full_id;
   msg->tid = htonl (t->id.tid);
   msg->ttl = htonl (default_ttl);
@@ -6949,10 +7200,6 @@ handle_local_to_origin (void *cls, struct GNUNET_SERVER_Client *client,
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Tunnel %X unknown.\n", tid);
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  for client %u.\n", c->id);
-    if (t->owner == c)
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is owner)\n");
-    else
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is leaf)\n");
     GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
@@ -7061,10 +7308,7 @@ handle_local_multicast (void *cls, struct GNUNET_SERVER_Client *client,
     GNUNET_break (0);
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Tunnel %X unknown.\n", tid);
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  for client %u.\n", c->id);
-    if (t->owner == c)
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is owner)\n");
-    else
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is leaf)\n");    GNUNET_break (0);
+    GNUNET_break (0);
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
@@ -7103,7 +7347,7 @@ handle_local_multicast (void *cls, struct GNUNET_SERVER_Client *client,
     handle_mesh_data_multicast (client, &my_full_id, &copy->header, NULL, 0);
   }
 
-  /* receive done gets called when last copy is sent to a neighbor */
+  GNUNET_SERVER_receive_done (t->owner->handle, GNUNET_OK);
   return;
 }
 
@@ -7143,13 +7387,9 @@ handle_local_ack (void *cls, struct GNUNET_SERVER_Client *client,
   t = tunnel_get_by_local_id (c, tid);
   if (NULL == t)
   {
-    GNUNET_break (0); // FIXME fc
+    GNUNET_break (0);
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "Tunnel %X unknown.\n", tid);
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  for client %u.\n", c->id);
-    if (t->owner == c)
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is owner)\n");
-    else
-      GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "  (client is leaf)\n");
     GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
     return;
   }
@@ -7594,6 +7834,9 @@ run (void *cls, struct GNUNET_SERVER_Handle *server,
   GNUNET_CRYPTO_hash (&my_public_key, sizeof (my_public_key),
                       &my_full_id.hashPubKey);
   myid = GNUNET_PEER_intern (&my_full_id);
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Mesh for peer [%s] starting\n",
+              GNUNET_i2s(&my_full_id));
 
 //   transport_handle = GNUNET_TRANSPORT_connect(c,
 //                                               &my_full_id,
@@ -7668,5 +7911,10 @@ main (int argc, char *const *argv)
 
   INTERVAL_SHOW;
 
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Mesh for peer [%s] FWD ACKs %u, BCK ACKs %u\n",
+              GNUNET_i2s(&my_full_id), debug_fwd_ack, debug_bck_ack);
+  
+
   return ret;
 }