Allow the number of incoming connections to be limited

It was already possible to limit outgoing connections. One might want
to do this on home network connections with high bandwidth but low
usage caps.

1 files changed, 54 insertions, 3 deletions

diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index 5f00e97f0..3445674f6 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -85,6 +85,7 @@ namespace nodetool
     command_line::add_arg(desc, arg_p2p_hide_my_port);
     command_line::add_arg(desc, arg_no_igd);
     command_line::add_arg(desc, arg_out_peers);
+    command_line::add_arg(desc, arg_in_peers);
     command_line::add_arg(desc, arg_tos_flag);
     command_line::add_arg(desc, arg_limit_rate_up);
     command_line::add_arg(desc, arg_limit_rate_down);
@@ -315,6 +316,9 @@ namespace nodetool
     if ( !set_max_out_peers(vm, command_line::get_arg(vm, arg_out_peers) ) )
       return false;
 
+    if ( !set_max_in_peers(vm, command_line::get_arg(vm, arg_in_peers) ) )
+      return false;
+
     if ( !set_tos_flag(vm, command_line::get_arg(vm, arg_tos_flag) ) )
       return false;
 
@@ -565,14 +569,23 @@ namespace nodetool
       while (!is_closing && !m_net_server.is_stop_signal_sent())
       { // main loop of thread
         //number_of_peers = m_net_server.get_config_object().get_connections_count();
-        unsigned int number_of_peers = 0;
+        unsigned int number_of_in_peers = 0;
+        unsigned int number_of_out_peers = 0;
         m_net_server.get_config_object().foreach_connection([&](const p2p_connection_context& cntxt)
         {
-          if (!cntxt.m_is_income) ++number_of_peers;
+          if (cntxt.m_is_income)
+          {
+            ++number_of_in_peers;
+          }
+          else
+          {
+            ++number_of_out_peers;
+          }
           return true;
         }); // lambda
 
-        m_current_number_of_out_peers = number_of_peers;
+        m_current_number_of_in_peers = number_of_in_peers;
+        m_current_number_of_out_peers = number_of_out_peers;
 
         boost::this_thread::sleep_for(boost::chrono::seconds(1));
       } // main loop of thread
@@ -1253,6 +1266,20 @@ namespace nodetool
   }
   //-----------------------------------------------------------------------------------
   template<class t_payload_net_handler>
+  size_t node_server<t_payload_net_handler>::get_incoming_connections_count()
+  {
+    size_t count = 0;
+    m_net_server.get_config_object().foreach_connection([&](const p2p_connection_context& cntxt)
+    {
+      if(cntxt.m_is_income)
+        ++count;
+      return true;
+    });
+
+    return count;
+  }
+  //-----------------------------------------------------------------------------------
+  template<class t_payload_net_handler>
   bool node_server<t_payload_net_handler>::idle_worker()
   {
     m_peer_handshake_idle_maker_interval.do_call(boost::bind(&node_server<t_payload_net_handler>::peer_sync_idle_maker, this));
@@ -1618,6 +1645,13 @@ namespace nodetool
       return 1;
     }
 
+   if (m_current_number_of_in_peers >= m_config.m_net_config.max_in_connection_count) // in peers limit
+    {
+      LOG_WARNING_CC(context, "COMMAND_HANDSHAKE came, but already have max incoming connections, so dropping this one.");
+      drop_connection(context);
+      return 1;
+    }
+
     if(!m_payload_handler.process_payload_sync_data(arg.payload_data, context, true))
     {
       LOG_WARNING_CC(context, "COMMAND_HANDSHAKE came, but process_payload_sync_data returned false, dropping connection.");
@@ -1787,12 +1821,29 @@ namespace nodetool
   }
 
   template<class t_payload_net_handler>
+  bool node_server<t_payload_net_handler>::set_max_in_peers(const boost::program_options::variables_map& vm, int64_t max)
+  {
+    if(max == -1) {
+      m_config.m_net_config.max_in_connection_count = -1;
+      return true;
+    }
+    m_config.m_net_config.max_in_connection_count = max;
+    return true;
+  }
+
+  template<class t_payload_net_handler>
   void node_server<t_payload_net_handler>::delete_out_connections(size_t count)
   {
     m_net_server.get_config_object().del_out_connections(count);
   }
 
   template<class t_payload_net_handler>
+  void node_server<t_payload_net_handler>::delete_in_connections(size_t count)
+  {
+    m_net_server.get_config_object().del_in_connections(count);
+  }
+
+  template<class t_payload_net_handler>
   bool node_server<t_payload_net_handler>::set_tos_flag(const boost::program_options::variables_map& vm, int flag)
   {
     if(flag==-1){