Lua plugin support for connection exempt list (#12849)

* Update ts_lua_misc.cc to add connection limit exempt list functions.

* Add Lua plugin documentation for connection limit exempt list APIs

* Update lua.en.rst

* Update ts_lua_misc.cc

* Refactor ts_lua_connection_limit_exempt_list_clear function

Author: shukitchan

doc/admin-guide/plugins/lua.en.rst

@@ -452,6 +452,73 @@ Here is an example:
 
 :ref:`TOP <admin-plugins-ts-lua>`
 
+ts.connection_limit_exempt_list_add
+------------------------------------
+**syntax:** *success = ts.connection_limit_exempt_list_add(IP_RANGES)*
+
+**context:** global
+
+**description**: Add IP ranges to the per-client connection limit exempt list. This function wraps the TSConnectionLimitExemptListAdd API.
+
+The IP_RANGES parameter should be a string containing one or more IP address ranges in CIDR notation, separated by commas. Client connections from these IP ranges will be exempt from per-client connection limits.
+
+Returns true on success, false on failure.
+
+Here is an example:
+
+::
+
+       if ts.connection_limit_exempt_list_add('10.0.0.0/8,192.168.1.0/24') then
+           ts.debug('Successfully added IP ranges to exempt list')
+       else
+           ts.error('Failed to add IP ranges to exempt list')
+       end
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.connection_limit_exempt_list_remove
+---------------------------------------
+**syntax:** *success = ts.connection_limit_exempt_list_remove(IP_RANGES)*
+
+**context:** global
+
+**description**: Remove IP ranges from the per-client connection limit exempt list. This function wraps the TSConnectionLimitExemptListRemove API.
+
+The IP_RANGES parameter should be a string containing one or more IP address ranges in CIDR notation, separated by commas.
+
+Returns true on success, false on failure.
+
+Here is an example:
+
+::
+
+       if ts.connection_limit_exempt_list_remove('192.168.1.0/24') then
+           ts.debug('Successfully removed IP range from exempt list')
+       else
+           ts.error('Failed to remove IP range from exempt list')
+       end
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
+ts.connection_limit_exempt_list_clear
+--------------------------------------
+**syntax:** *ts.connection_limit_exempt_list_clear()*
+
+**context:** global
+
+**description**: Clear all IP ranges from the per-client connection limit exempt list. This function wraps the TSConnectionLimitExemptListClear API.
+
+This function removes all entries from the exempt list.
+
+Here is an example:
+
+::
+
+       ts.connection_limit_exempt_list_clear()
+       ts.debug('Cleared connection limit exempt list')
+
+:ref:`TOP <admin-plugins-ts-lua>`
+
 Remap status constants
 ----------------------
 **context:** do_remap

plugins/lua/ts_lua_misc.cc

@@ -40,6 +40,9 @@ static int ts_lua_get_config_dir(lua_State *L);
 static int ts_lua_get_runtime_dir(lua_State *L);
 static int ts_lua_get_plugin_dir(lua_State *L);
 static int ts_lua_get_traffic_server_version(lua_State *L);
+static int ts_lua_connection_limit_exempt_list_add(lua_State *L);
+static int ts_lua_connection_limit_exempt_list_remove(lua_State *L);
+static int ts_lua_connection_limit_exempt_list_clear(lua_State *L);
 
 static int ts_lua_sleep_cleanup(ts_lua_async_item *ai);
 static int ts_lua_sleep_handler(TSCont contp, TSEvent event, void *edata);
@@ -136,6 +139,18 @@ ts_lua_inject_misc_api(lua_State *L)
   lua_pushcfunction(L, ts_lua_get_traffic_server_version);
   lua_setfield(L, -2, "get_traffic_server_version");
 
+  /* ts.connection_limit_exempt_list_add(...) */
+  lua_pushcfunction(L, ts_lua_connection_limit_exempt_list_add);
+  lua_setfield(L, -2, "connection_limit_exempt_list_add");
+
+  /* ts.connection_limit_exempt_list_remove(...) */
+  lua_pushcfunction(L, ts_lua_connection_limit_exempt_list_remove);
+  lua_setfield(L, -2, "connection_limit_exempt_list_remove");
+
+  /* ts.connection_limit_exempt_list_clear(...) */
+  lua_pushcfunction(L, ts_lua_connection_limit_exempt_list_clear);
+  lua_setfield(L, -2, "connection_limit_exempt_list_clear");
+
   ts_lua_inject_misc_variables(L);
 }
 
@@ -631,3 +646,54 @@ ts_lua_get_traffic_server_version(lua_State *L)
   lua_pushstring(L, s);
   return 1;
 }
+
+static int
+ts_lua_connection_limit_exempt_list_add(lua_State *L)
+{
+  size_t      len;
+  const char *ip_ranges;
+
+  ip_ranges = luaL_checklstring(L, 1, &len);
+
+  if (ip_ranges && len > 0) {
+    TSReturnCode ret = TSConnectionLimitExemptListAdd(std::string_view(ip_ranges, len));
+    if (ret == TS_SUCCESS) {
+      lua_pushboolean(L, 1);
+    } else {
+      lua_pushboolean(L, 0);
+    }
+  } else {
+    lua_pushboolean(L, 0);
+  }
+
+  return 1;
+}
+
+static int
+ts_lua_connection_limit_exempt_list_remove(lua_State *L)
+{
+  size_t      len;
+  const char *ip_ranges;
+
+  ip_ranges = luaL_checklstring(L, 1, &len);
+
+  if (ip_ranges && len > 0) {
+    TSReturnCode ret = TSConnectionLimitExemptListRemove(std::string_view(ip_ranges, len));
+    if (ret == TS_SUCCESS) {
+      lua_pushboolean(L, 1);
+    } else {
+      lua_pushboolean(L, 0);
+    }
+  } else {
+    lua_pushboolean(L, 0);
+  }
+
+  return 1;
+}
+
+static int
+ts_lua_connection_limit_exempt_list_clear(lua_State * /* L ATS_UNUSED */)
+{
+  TSConnectionLimitExemptListClear();
+  return 0;
+}