%%%----------------------------------------------------------------------
%%% 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) 2002-2013 ProcessOne
%%%
%%% 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([start/0, new/1, new1/1, update/2,
transform_options/1, load_from_config/0]).
-include("ejabberd.hrl").
-include("logger.hrl").
-record(maxrate, {maxrate = 0 :: integer(),
lastrate = 0.0 :: float(),
lasttime = 0 :: integer()}).
-record(shaper, {name :: {atom(), global},
maxrate :: integer()}).
-type shaper() :: none | #maxrate{}.
-export_type([shaper/0]).
-spec start() -> ok.
start() ->
mnesia:create_table(shaper,
[{ram_copies, [node()]},
{local_content, true},
{attributes, record_info(fields, shaper)}]),
mnesia:add_table_copy(shaper, node(), ram_copies),
load_from_config(),
ok.
-spec load_from_config() -> ok | {error, any()}.
load_from_config() ->
Shapers = ejabberd_config:get_option(
shaper, fun(V) -> V end, []),
case mnesia:transaction(
fun() ->
lists:foreach(
fun({Name, MaxRate}) ->
mnesia:write(#shaper{name = {Name, global},
maxrate = MaxRate})
end, Shapers)
end) of
{atomic, ok} ->
ok;
Err ->
{error, Err}
end.
-spec new(atom()) -> shaper().
new(none) ->
none;
new(Name) ->
MaxRate = case ets:lookup(shaper, {Name, global}) of
[#shaper{maxrate = R}] ->
R;
[] ->
?WARNING_MSG("Attempt to initialize an "
"unspecified shaper '~s'", [Name]),
none
end,
new1(MaxRate).
-spec new1(none | integer()) -> shaper().
new1(none) -> none;
new1(MaxRate) ->
#maxrate{maxrate = MaxRate, lastrate = 0.0,
lasttime = now_to_usec(now())}.
-spec update(shaper(), integer()) -> {shaper(), integer()}.
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}.
transform_options(Opts) ->
lists:foldl(fun transform_options/2, [], Opts).
transform_options({OptName, Name, {maxrate, N}}, Opts) when OptName == shaper ->
[{shaper, [{Name, N}]}|Opts];
transform_options({OptName, Name, none}, Opts) when OptName == shaper ->
[{shaper, [{Name, none}]}|Opts];
transform_options(Opt, Opts) ->
[Opt|Opts].
now_to_usec({MSec, Sec, USec}) ->
(MSec * 1000000 + Sec) * 1000000 + USec.
