GH-459 Reset sync_known_lib_num and sync_last_requested_num when unab…

…le to request range. Verify request is above LIB.

plugins/net_plugin/net_plugin.cpp

@@ -2113,6 +2113,7 @@ namespace eosio {
  }
  if (conns.size() == 1) { // only one available
  ++sync_ordinal;
+ fc_dlog(logger, "sync from ${c}", ("c", conns.front()->connection_id));
  conns.front()->sync_ordinal = sync_ordinal.load();
  return conns.front();
  }
@@ -2155,23 +2156,27 @@ namespace eosio {
  * a provider is supplied and able to be used, use it.
  * otherwise select the next available from the list, round-robin style.
  */
+ connection_ptr new_sync_source = (conn && conn->current()) ? conn : find_next_sync_node();
 
- connection_ptr new_sync_source = (conn && conn->current()) ? conn :
- find_next_sync_node();
+ auto reset_on_failure = [&]() {
+ sync_source.reset();
+ sync_known_lib_num = chain_info.lib_num;
+ sync_last_requested_num = 0;
+ // not in sync, but need to be out of lib_catchup for start_sync to work
+ set_state( in_sync );
+ send_handshakes();
+ };
 
  // verify there is an available source
  if( !new_sync_source ) {
  fc_wlog( logger, "Unable to continue syncing at this time");
- sync_source.reset();
- sync_known_lib_num = chain_info.lib_num;
- sync_last_requested_num = 0;
- set_state( in_sync ); // probably not, but we can't do anything else
+ reset_on_failure();
  return;
  }
 
  bool request_sent = false;
  if( sync_last_requested_num != sync_known_lib_num ) {
- uint32_t start = sync_next_expected_num;
+ uint32_t start = std::min(sync_next_expected_num, chain_info.lib_num+1);
  uint32_t end = start + sync_req_span - 1;
  if( end > sync_known_lib_num )
  end = sync_known_lib_num;
@@ -2186,10 +2191,8 @@ namespace eosio {
  }
  }
  if( !request_sent ) {
- sync_source.reset();
  fc_wlog(logger, "Unable to request range, sending handshakes to everyone");
- set_state( in_sync ); // need to be out of lib_catchup so start_sync will work
- send_handshakes();
+ reset_on_failure();
  }
  }