From ac95589b0c3f54a7991b1461028fdb5e47c887db Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Wed, 22 Feb 2017 11:40:46 +0100
Subject: [PATCH] try to fix BF size mess created by original BLOCK API change

---
 src/dht/gnunet-service-dht_clients.c    |  4 +-
 src/dht/gnunet-service-dht_neighbours.c |  6 ++-
 src/dht/plugin_block_dht.c              | 57 +++++++++++++++++++++++--
 src/fs/plugin_block_fs.c                |  3 +-
 4 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/src/dht/gnunet-service-dht_clients.c b/src/dht/gnunet-service-dht_clients.c
index a42356e5f..c304f2e54 100644
--- a/src/dht/gnunet-service-dht_clients.c
+++ b/src/dht/gnunet-service-dht_clients.c
@@ -374,7 +374,9 @@ transmit_request (struct ClientQueryRecord *cqr)
                                   GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
                                                             UINT32_MAX),
                                   NULL,
-                                  0);
+                                  0,
+                                  "seen-set-size",
+                                  cqr->seen_replies_count);
   GNUNET_BLOCK_group_set_seen (bg,
                                cqr->seen_replies,
                                cqr->seen_replies_count);
diff --git a/src/dht/gnunet-service-dht_neighbours.c b/src/dht/gnunet-service-dht_neighbours.c
index 975872f1b..6eef05c20 100644
--- a/src/dht/gnunet-service-dht_neighbours.c
+++ b/src/dht/gnunet-service-dht_neighbours.c
@@ -661,7 +661,9 @@ send_find_peer_message (void *cls)
                                   GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
                                                             UINT32_MAX),
                                   NULL,
-                                  0);
+                                  0,
+                                  "filter-size",
+                                  DHT_BLOOM_SIZE);
   GNUNET_CONTAINER_multipeermap_iterate (all_connected_peers,
                                          &add_known_to_bloom,
                                          bg);
@@ -2087,6 +2089,8 @@ handle_dht_p2p_get (void *cls,
                                   type,
                                   get->bf_mutator,
                                   &xquery[xquery_size],
+                                  reply_bf_size,
+                                  "filter-size",
                                   reply_bf_size);
   /* remember request for routing replies */
   GDS_ROUTING_add (peer->id,
diff --git a/src/dht/plugin_block_dht.c b/src/dht/plugin_block_dht.c
index 168497440..869ec1554 100644
--- a/src/dht/plugin_block_dht.c
+++ b/src/dht/plugin_block_dht.c
@@ -34,9 +34,41 @@
 #define DEBUG_DHT GNUNET_EXTRA_LOGGING
 
 /**
- * How big is the BF we use for DHT blocks?
+ * Number of bits we set per entry in the bloomfilter.
+ * Do not change!
  */
-#define DHT_BF_SIZE 8
+#define BLOOMFILTER_K 16
+
+
+/**
+ * How many bytes should a bloomfilter be if we have already seen
+ * entry_count responses?  Note that #GNUNET_CONSTANTS_BLOOMFILTER_K
+ * gives us the number of bits set per entry.  Furthermore, we should
+ * not re-size the filter too often (to keep it cheap).
+ *
+ * Since other peers will also add entries but not resize the filter,
+ * we should generally pick a slightly larger size than what the
+ * strict math would suggest.
+ *
+ * @param entry_count expected number of entries in the Bloom filter
+ * @return must be a power of two and smaller or equal to 2^15.
+ */
+static size_t
+compute_bloomfilter_size (unsigned int entry_count)
+{
+  size_t size;
+  unsigned int ideal = (entry_count * BLOOMFILTER_K) / 4;
+  uint16_t max = 1 << 15;
+
+  if (entry_count > max)
+    return max;
+  size = 8;
+  while ((size < max) && (size < ideal))
+    size *= 2;
+  if (size > max)
+    return max;
+  return size;
+}
 
 
 /**
@@ -59,9 +91,26 @@ block_plugin_dht_create_group (void *cls,
                                size_t raw_data_size,
                                va_list va)
 {
+  unsigned int bf_size;
+  const char *guard;
+
+  guard = va_arg (va, const char *);
+  if (0 != memcmp (guard,
+                   "seen-set-size",
+                   strlen ("seen-set-size")))
+    bf_size = compute_bloomfilter_size (va_arg (va, unsigned int));
+  else if (0 == memcmp (va_arg (va, const char *),
+                        "filter-size",
+                        strlen ("filter-size")))
+    bf_size = va_arg (va, unsigned int);
+  else
+  {
+    GNUNET_break (0);
+    bf_size = 8;
+  }
   return GNUNET_BLOCK_GROUP_bf_create (cls,
-                                       DHT_BF_SIZE,
-                                       GNUNET_CONSTANTS_BLOOMFILTER_K,
+                                       bf_size,
+                                       BLOOMFILTER_K,
                                        type,
                                        nonce,
                                        raw_data,
diff --git a/src/fs/plugin_block_fs.c b/src/fs/plugin_block_fs.c
index 6c574fca2..5ccbd237e 100644
--- a/src/fs/plugin_block_fs.c
+++ b/src/fs/plugin_block_fs.c
@@ -28,7 +28,6 @@
 #include "gnunet_fs_service.h"
 #include "block_fs.h"
 #include "gnunet_signatures.h"
-#include "gnunet_constants.h"
 #include "gnunet_block_group_lib.h"
 
 
@@ -56,7 +55,7 @@ static size_t
 compute_bloomfilter_size (unsigned int entry_count)
 {
   size_t size;
-  unsigned int ideal = (entry_count * GNUNET_CONSTANTS_BLOOMFILTER_K) / 4;
+  unsigned int ideal = (entry_count * BLOOMFILTER_K) / 4;
   uint16_t max = 1 << 15;
 
   if (entry_count > max)
-- 
2.25.1