cryptonote_protocol: misc fixes to the new sync algorithm

Fix sync wedge corner case:
It could happen if a connection went into standby mode, while
it was the one which had requested the next span, and that span
was still waiting for the data, and that peer is not on the
main chain. Other peers can then start asking for that data
again and again, but never get it as only that forked peer does.

And various other fixes

1 files changed, 25 insertions, 3 deletions

diff --git a/src/cryptonote_protocol/block_queue.cpp b/src/cryptonote_protocol/block_queue.cpp
index 94d31404e..02a8e3ec2 100644
--- a/src/cryptonote_protocol/block_queue.cpp
+++ b/src/cryptonote_protocol/block_queue.cpp
@@ -52,8 +52,11 @@ namespace cryptonote
 void block_queue::add_blocks(uint64_t height, std::list<cryptonote::block_complete_entry> bcel, const boost::uuids::uuid &connection_id, float rate, size_t size)
 {
   boost::unique_lock<boost::recursive_mutex> lock(mutex);
-  remove_span(height);
+  std::list<crypto::hash> hashes;
+  bool has_hashes = remove_span(height, &hashes);
   blocks.insert(span(height, std::move(bcel), connection_id, rate, size));
+  if (has_hashes)
+    set_span_hashes(height, connection_id, hashes);
 }
 
 void block_queue::add_blocks(uint64_t height, uint64_t nblocks, const boost::uuids::uuid &connection_id, boost::posix_time::ptime time)
@@ -92,17 +95,20 @@ void block_queue::flush_stale_spans(const std::set<boost::uuids::uuid> &live_con
   }
 }
 
-void block_queue::remove_span(uint64_t start_block_height)
+bool block_queue::remove_span(uint64_t start_block_height, std::list<crypto::hash> *hashes)
 {
   boost::unique_lock<boost::recursive_mutex> lock(mutex);
   for (block_map::iterator i = blocks.begin(); i != blocks.end(); ++i)
   {
     if (i->start_block_height == start_block_height)
     {
+      if (hashes)
+        *hashes = std::move(i->hashes);
       blocks.erase(i);
-      return;
+      return true;
     }
   }
+  return false;
 }
 
 void block_queue::remove_spans(const boost::uuids::uuid &connection_id, uint64_t start_block_height)
@@ -278,6 +284,22 @@ bool block_queue::get_next_span(uint64_t &height, std::list<cryptonote::block_co
   return false;
 }
 
+bool block_queue::has_next_span(const boost::uuids::uuid &connection_id, bool &filled) const
+{
+  boost::unique_lock<boost::recursive_mutex> lock(mutex);
+  if (blocks.empty())
+    return false;
+  block_map::const_iterator i = blocks.begin();
+  if (is_blockchain_placeholder(*i))
+    ++i;
+  if (i == blocks.end())
+    return false;
+  if (i->connection_id != connection_id)
+    return false;
+  filled = !i->blocks.empty();
+  return true;
+}
+
 size_t block_queue::get_data_size() const
 {
   boost::unique_lock<boost::recursive_mutex> lock(mutex);