Add gray peer list housekeeping system

A random peer from the gray peer list is selected and a connection is
made to check if the peer is alive.

If the connection and handshake are successful the peer is promoted to
the white peer list, in case of failure the peer is evicted from the
gray peer list.

The connection is closed after the check in either case.

1 files changed, 71 insertions, 0 deletions

diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index 60e51c222..3933fe65b 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -926,6 +926,50 @@ namespace nodetool
     return true;
   }
 
+  template<class t_payload_net_handler>
+  bool node_server<t_payload_net_handler>::check_connection_and_handshake_with_peer(const net_address& na, uint64_t last_seen_stamp)
+  {
+    LOG_PRINT_L1("Connecting to " << epee::string_tools::get_ip_string_from_int32(na.ip)  << ":"
+                                  << epee::string_tools::num_to_string_fast(na.port) << "(last_seen: "
+                                  << (last_seen_stamp ? epee::misc_utils::get_time_interval_string(time(NULL) - last_seen_stamp):"never")
+                                  << ")...");
+
+    typename net_server::t_connection_context con = AUTO_VAL_INIT(con);
+    bool res = m_net_server.connect(epee::string_tools::get_ip_string_from_int32(na.ip),
+                                    epee::string_tools::num_to_string_fast(na.port),
+                                    m_config.m_net_config.connection_timeout,
+                                    con);
+
+    if (!res) {
+      bool is_priority = is_priority_node(na);
+
+      LOG_PRINT_CC_PRIORITY_NODE(is_priority, con, "Connect failed to "
+              << epee::string_tools::get_ip_string_from_int32(na.ip)
+              << ":" << epee::string_tools::num_to_string_fast(na.port));
+
+      return false;
+    }
+
+    peerid_type pi = AUTO_VAL_INIT(pi);
+    res = do_handshake_with_peer(pi, con, true);
+
+    if (!res) {
+      bool is_priority = is_priority_node(na);
+
+      LOG_PRINT_CC_PRIORITY_NODE(is_priority, con, "Failed to HANDSHAKE with peer "
+              << epee::string_tools::get_ip_string_from_int32(na.ip)
+              << ":" << epee::string_tools::num_to_string_fast(na.port));
+
+      return false;
+    }
+
+    m_net_server.get_config_object().close(con.m_connection_id);
+
+    LOG_PRINT_CC_GREEN(con, "CONNECTION HANDSHAKED OK AND CLOSED.", LOG_LEVEL_2);
+
+    return true;
+  }
+
 #undef LOG_PRINT_CC_PRIORITY_NODE
 
   //-----------------------------------------------------------------------------------
@@ -1097,6 +1141,7 @@ namespace nodetool
   {
     m_peer_handshake_idle_maker_interval.do_call(boost::bind(&node_server<t_payload_net_handler>::peer_sync_idle_maker, this));
     m_connections_maker_interval.do_call(boost::bind(&node_server<t_payload_net_handler>::connections_maker, this));
+    m_gray_peerlist_housekeeping_interval.do_call(boost::bind(&node_server<t_payload_net_handler>::gray_peerlist_housekeeping, this));
     m_peerlist_store_interval.do_call(boost::bind(&node_server<t_payload_net_handler>::store_config, this));
     return true;
   }
@@ -1704,4 +1749,30 @@ namespace nodetool
 
     return count > max_connections;
   }
+
+  template<class t_payload_net_handler>
+  bool node_server<t_payload_net_handler>::gray_peerlist_housekeeping()
+  {
+    peerlist_entry pe = AUTO_VAL_INIT(pe);
+
+    if (!m_peerlist.get_gray_peer_random(pe)) {
+        return false;
+    }
+
+    bool success = check_connection_and_handshake_with_peer(pe.adr, pe.last_seen);
+
+    if (!success) {
+      m_peerlist.remove_from_peer_gray(pe);
+
+      LOG_PRINT_L2("PEER EVICTED FROM GRAY PEER LIST IP address: " << epee::string_tools::get_ip_string_from_int32(pe.adr.ip) << " Peer ID: " << std::hex << pe.id);
+
+      return true;
+    }
+
+    m_peerlist.append_with_peer_white(pe);
+
+    LOG_PRINT_L2("PEER PROMOTED TO WHITE PEER LIST IP address: " << epee::string_tools::get_ip_string_from_int32(pe.adr.ip) << " Peer ID: " << std::hex << pe.id);
+
+    return true;
+  }
 }