%%%----------------------------------------------------------------------
%%% File : shaper.erl
%%% Author : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Functions to control connections traffic
%%% Created : 9 Feb 2003 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2008 Process-one
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License
%%% along with this program; if not, write to the Free Software
%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------
-module(shaper).
-author('alexey@process-one.net').
-export([new/1, new1/1, update/2]).
-include("ejabberd.hrl").
-record(maxrate, {maxrate, lastrate, lasttime}).
new(Name) ->
Data = case ejabberd_config:get_global_option({shaper, Name, global}) of
undefined ->
none;
D ->
D
end,
new1(Data).
new1(none) ->
none;
new1({maxrate, MaxRate}) ->
#maxrate{maxrate = MaxRate,
lastrate = 0,
lasttime = now_to_usec(now())}.
update(none, _Size) ->
{none, 0};
update(#maxrate{} = State, Size) ->
MinInterv = 1000 * Size /
(2 * State#maxrate.maxrate - State#maxrate.lastrate),
Interv = (now_to_usec(now()) - State#maxrate.lasttime) / 1000,
?DEBUG("State: ~p, Size=~p~nM=~p, I=~p~n",
[State, Size, MinInterv, Interv]),
Pause = if
MinInterv > Interv ->
1 + trunc(MinInterv - Interv);
true ->
0
end,
NextNow = now_to_usec(now()) + Pause * 1000,
{State#maxrate{
lastrate = (State#maxrate.lastrate +
1000000 * Size / (NextNow - State#maxrate.lasttime))/2,
lasttime = NextNow},
Pause}.
now_to_usec({MSec, Sec, USec}) ->
(MSec*1000000 + Sec)*1000000 + USec.
