From 55a05c2bb7a733c22c05a2f816dcbeb01fdf6da1 Mon Sep 17 00:00:00 2001
From: Simone Mainardi <mainardi@ntop.org>
Date: Fri, 21 Dec 2018 17:41:03 +0100
Subject: [PATCH] Limits the maximum number of nIndex interfaces

---
 include/NetworkInterface.h        |  2 +-
 include/ntop_defines.h            |  4 ++++
 scripts/lua/modules/lua_utils.lua |  8 +++++---
 src/LuaEngine.cpp                 |  9 +++++++++
 src/NetworkInterface.cpp          | 16 +++++++++++++---
 src/Ntop.cpp                      |  2 +-
 src/Prefs.cpp                     |  2 +-
 7 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/include/NetworkInterface.h b/include/NetworkInterface.h
index 6bdc5c412937..0fff96304f7a 100644
--- a/include/NetworkInterface.h
+++ b/include/NetworkInterface.h
@@ -252,7 +252,7 @@ class NetworkInterface : public Checkpointable {
   NetworkInterface(const char *name, const char *custom_interface_type = NULL);
   virtual ~NetworkInterface();
 
-  void finishInitialization();
+  void finishInitialization(u_int8_t num_defined_interfaces);
   virtual u_int32_t getASesHashSize();
   virtual u_int32_t getCountriesHashSize();
   virtual u_int32_t getVLANsHashSize();
diff --git a/include/ntop_defines.h b/include/ntop_defines.h
index 80722555bd23..acbb3679f7b9 100644
--- a/include/ntop_defines.h
+++ b/include/ntop_defines.h
@@ -732,6 +732,10 @@
 // MySQL-related defined
 #define MYSQL_MAX_NUM_FIELDS  255
 #define MYSQL_MAX_NUM_ROWS    1000
+// nIndex-related
+#ifdef HAVE_NINDEX
+#define NINDEX_MAX_NUM_INTERFACES 8
+#endif
 
 #ifdef NTOPNG_PRO
 #define MYSQL_TOP_TALKERS_CONSOLIDATION_FREQ 20
diff --git a/scripts/lua/modules/lua_utils.lua b/scripts/lua/modules/lua_utils.lua
index 243f25456088..8fec81091b23 100644
--- a/scripts/lua/modules/lua_utils.lua
+++ b/scripts/lua/modules/lua_utils.lua
@@ -745,10 +745,12 @@ function hasNindexSupport()
    if prefs == nil then
     prefs = ntop.getPrefs()
    end
-   local rc = prefs.is_nindex_enabled
 
-   if(rc == nil) then rc = false end
-   return rc
+   if prefs.is_nindex_enabled and interface.nIndexEnabled() then
+      return true
+   end
+
+   return false
 end
 
 --for _key, _value in pairsByKeys(vals, rev) do
diff --git a/src/LuaEngine.cpp b/src/LuaEngine.cpp
index 2773e396405d..e294bda7d181 100644
--- a/src/LuaEngine.cpp
+++ b/src/LuaEngine.cpp
@@ -4094,6 +4094,14 @@ static int ntop_nindex_topk(lua_State* vm) {
 		      max_num_hits, topToBottomSort));
 }
 
+static int ntop_nindex_enabed(lua_State* vm) {
+  NetworkInterface *ntop_interface = getCurrentInterface(vm);
+
+  lua_pushboolean(vm, ntop_interface && ntop_interface->getNindex());
+
+  return(CONST_LUA_OK);
+}
+
 #endif
 
 /* ****************************************** */
@@ -8074,6 +8082,7 @@ static const luaL_Reg ntop_interface_reg[] = {
 
 #if defined(HAVE_NINDEX) && defined(NTOPNG_PRO)
   /* nIndex */
+  { "nIndexEnabled",                   ntop_nindex_enabed              },
   { "nIndexSelect",                    ntop_nindex_select              },
   { "nIndexTopK",                      ntop_nindex_topk                },
 #endif
diff --git a/src/NetworkInterface.cpp b/src/NetworkInterface.cpp
index da4f277ecfac..928f216a0762 100644
--- a/src/NetworkInterface.cpp
+++ b/src/NetworkInterface.cpp
@@ -6661,12 +6661,22 @@ void NetworkInterface::checkMacIPAssociation(bool triggerEvent, u_char *_mac, u_
   Put here all the code that is executed when the NIC initialization
   is succesful
  */
-void NetworkInterface::finishInitialization() {
+void NetworkInterface::finishInitialization(u_int8_t num_defined_interfaces) {
   if(!isView()) {
 #if defined(NTOPNG_PRO) && defined(HAVE_NINDEX)
     if(ntop->getPrefs()->is_enterprise_edition() && ntop->getPrefs()->do_dump_flows_on_nindex()) {
-      db = new NIndexFlowDB(this);
-      goto enable_aggregation;
+      if(num_defined_interfaces + 1 >= NINDEX_MAX_NUM_INTERFACES) {
+	ntop->getTrace()->traceEvent(TRACE_ERROR,
+				     "nIndex cannot be enabled for %s.", get_name());
+	ntop->getTrace()->traceEvent(TRACE_ERROR,
+				     "The maximum number of interfaces that can be used with nIndex is %d.",
+				     NINDEX_MAX_NUM_INTERFACES);
+	ntop->getTrace()->traceEvent(TRACE_ERROR,
+				     "Interface will continue to work without nIndex support.");
+      } else {
+	db = new NIndexFlowDB(this);
+	goto enable_aggregation;
+      }
     }
 #endif
 
diff --git a/src/Ntop.cpp b/src/Ntop.cpp
index af69f20b3735..f8350072a196 100644
--- a/src/Ntop.cpp
+++ b/src/Ntop.cpp
@@ -1980,7 +1980,7 @@ int Ntop::getInterfaceIdByName(lua_State *vm, const char * const name) {
 /* ****************************************** */
 
 void Ntop::registerInterface(NetworkInterface *_if) {
-  _if->finishInitialization();
+  _if->finishInitialization(num_defined_interfaces);
   _if->checkAggregationMode();
 
   for(int i = 0; i < num_defined_interfaces; i++) {
diff --git a/src/Prefs.cpp b/src/Prefs.cpp
index 41d1f1c2911b..2220a2f6dc78 100755
--- a/src/Prefs.cpp
+++ b/src/Prefs.cpp
@@ -1570,7 +1570,7 @@ void Prefs::lua(lua_State* vm) {
     lua_push_uint64_table_entry(vm, "flow_aggregation_frequency", flow_aggregation_frequency());
 
 #if defined(HAVE_NINDEX) && defined(NTOPNG_PRO)
-  lua_push_bool_table_entry(vm, "is_nindex_enabled", dump_flows_on_nindex);
+  lua_push_bool_table_entry(vm, "is_nindex_enabled", do_dump_flows_on_nindex());
 #endif
     
   if(mysql_dbname) lua_push_str_table_entry(vm, "mysql_dbname", mysql_dbname);