344 lines
10 KiB
Erlang
344 lines
10 KiB
Erlang
%%%-------------------------------------------------------------------
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%%% File : stun_codec.erl
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%%% Author : Evgeniy Khramtsov <ekhramtsov@process-one.net>
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%%% Description : STUN codec
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%%% Created : 7 Aug 2009 by Evgeniy Khramtsov <ekhramtsov@process-one.net>
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%%%
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%%%
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%%% ejabberd, Copyright (C) 2002-2012 ProcessOne
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%%%
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%%% This program is free software; you can redistribute it and/or
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%%% modify it under the terms of the GNU General Public License as
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%%% published by the Free Software Foundation; either version 2 of the
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%%% License, or (at your option) any later version.
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%%%
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%%% This program is distributed in the hope that it will be useful,
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%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
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%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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%%% General Public License for more details.
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%%%
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%%% You should have received a copy of the GNU General Public License
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%%% along with this program; if not, write to the Free Software
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%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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%%% 02111-1307 USA
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%%%
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%%%-------------------------------------------------------------------
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-module(stun_codec).
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%% API
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-export([decode/1,
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encode/1,
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version/1,
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reason/1,
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pp/1]).
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%% Tests
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-export([test_udp/2,
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test_tcp/2,
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test_tls/2,
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test_public/0]).
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-include("stun.hrl").
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%%====================================================================
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%% API
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%%====================================================================
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decode(<<0:2, Type:14, Len:16, Magic:32, TrID:96,
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Body:Len/binary, Tail/binary>>) ->
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case catch decode(Type, Magic, TrID, Body) of
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{'EXIT', _} ->
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{error, unparsed};
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Res ->
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{ok, Res, Tail}
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end;
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decode(<<0:2, _/binary>>) ->
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more;
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decode(<<>>) ->
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empty;
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decode(_) ->
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{error, unparsed}.
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encode(#stun{class = Class,
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method = Method,
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magic = Magic,
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trid = TrID} = Msg) ->
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ClassCode = case Class of
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request -> 0;
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indication -> 1;
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response -> 2;
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error -> 3
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end,
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Type = ?STUN_TYPE(ClassCode, Method),
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Attrs = enc_attrs(Msg),
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Len = size(Attrs),
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<<0:2, Type:14, Len:16, Magic:32, TrID:96, Attrs/binary>>.
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pp(Term) ->
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io_lib_pretty:print(Term, fun pp/2).
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version(#stun{magic = ?STUN_MAGIC}) ->
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new;
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version(#stun{}) ->
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old.
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reason(300) -> <<"Try Alternate">>;
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reason(400) -> <<"Bad Request">>;
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reason(401) -> <<"Unauthorized">>;
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reason(420) -> <<"Unknown Attribute">>;
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reason(438) -> <<"Stale Nonce">>;
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reason(500) -> <<"Server Error">>;
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reason(_) -> <<"Undefined Error">>.
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%%====================================================================
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%% Internal functions
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%%====================================================================
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decode(Type, Magic, TrID, Body) ->
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Method = ?STUN_METHOD(Type),
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Class = case ?STUN_CLASS(Type) of
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0 -> request;
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1 -> indication;
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2 -> response;
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3 -> error
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end,
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dec_attrs(Body, #stun{class = Class,
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method = Method,
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magic = Magic,
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trid = TrID}).
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dec_attrs(<<Type:16, Len:16, Rest/binary>>, Msg) ->
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PaddLen = padd_len(Len),
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<<Val:Len/binary, _:PaddLen, Tail/binary>> = Rest,
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NewMsg = dec_attr(Type, Val, Msg),
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if Type == ?STUN_ATTR_MESSAGE_INTEGRITY ->
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NewMsg;
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true ->
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dec_attrs(Tail, NewMsg)
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end;
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dec_attrs(<<>>, Msg) ->
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Msg.
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enc_attrs(Msg) ->
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list_to_binary(
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[enc_attr(?STUN_ATTR_SOFTWARE, Msg#stun.'SOFTWARE'),
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enc_addr(?STUN_ATTR_MAPPED_ADDRESS, Msg#stun.'MAPPED-ADDRESS'),
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enc_xor_addr(?STUN_ATTR_XOR_MAPPED_ADDRESS,
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Msg#stun.magic, Msg#stun.trid,
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Msg#stun.'XOR-MAPPED-ADDRESS'),
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enc_addr(?STUN_ATTR_ALTERNATE_SERVER, Msg#stun.'ALTERNATE-SERVER'),
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enc_attr(?STUN_ATTR_USERNAME, Msg#stun.'USERNAME'),
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enc_attr(?STUN_ATTR_REALM, Msg#stun.'REALM'),
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enc_attr(?STUN_ATTR_NONCE, Msg#stun.'NONCE'),
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enc_error_code(Msg#stun.'ERROR-CODE'),
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enc_unknown_attrs(Msg#stun.'UNKNOWN-ATTRIBUTES')]).
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dec_attr(?STUN_ATTR_MAPPED_ADDRESS, Val, Msg) ->
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<<_, Family, Port:16, AddrBin/binary>> = Val,
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Addr = dec_addr(Family, AddrBin),
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Msg#stun{'MAPPED-ADDRESS' = {Addr, Port}};
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dec_attr(?STUN_ATTR_XOR_MAPPED_ADDRESS, Val, Msg) ->
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<<_, Family, XPort:16, XAddr/binary>> = Val,
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Magic = Msg#stun.magic,
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Port = XPort bxor (Magic bsr 16),
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Addr = dec_xor_addr(Family, Magic, Msg#stun.trid, XAddr),
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Msg#stun{'XOR-MAPPED-ADDRESS' = {Addr, Port}};
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dec_attr(?STUN_ATTR_SOFTWARE, Val, Msg) ->
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Msg#stun{'SOFTWARE' = Val};
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dec_attr(?STUN_ATTR_USERNAME, Val, Msg) ->
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Msg#stun{'USERNAME' = Val};
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dec_attr(?STUN_ATTR_REALM, Val, Msg) ->
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Msg#stun{'REALM' = Val};
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dec_attr(?STUN_ATTR_NONCE, Val, Msg) ->
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Msg#stun{'NONCE' = Val};
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dec_attr(?STUN_ATTR_MESSAGE_INTEGRITY, Val, Msg) ->
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Msg#stun{'MESSAGE-INTEGRITY' = Val};
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dec_attr(?STUN_ATTR_ALTERNATE_SERVER, Val, Msg) ->
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<<_, Family, Port:16, Address/binary>> = Val,
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IP = dec_addr(Family, Address),
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Msg#stun{'ALTERNATE-SERVER' = {IP, Port}};
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dec_attr(?STUN_ATTR_ERROR_CODE, Val, Msg) ->
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<<_:21, Class:3, Number:8, Reason/binary>> = Val,
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if Class >=3, Class =< 6, Number >=0, Number =< 99 ->
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Code = Class * 100 + Number,
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Msg#stun{'ERROR-CODE' = {Code, Reason}}
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end;
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dec_attr(?STUN_ATTR_UNKNOWN_ATTRIBUTES, Val, Msg) ->
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Attrs = dec_unknown_attrs(Val, []),
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Msg#stun{'UNKNOWN-ATTRIBUTES' = Attrs};
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dec_attr(Attr, _Val, #stun{unsupported = Attrs} = Msg)
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when Attr =< 16#7fff ->
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Msg#stun{unsupported = [Attr|Attrs]};
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dec_attr(_Attr, _Val, Msg) ->
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Msg.
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dec_addr(1, <<A1, A2, A3, A4>>) ->
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{A1, A2, A3, A4};
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dec_addr(2, <<A1:16, A2:16, A3:16, A4:16,
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A5:16, A6:16, A7:16, A8:16>>) ->
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{A1, A2, A3, A4, A5, A6, A7, A8}.
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dec_xor_addr(1, Magic, _TrID, <<XAddr:32>>) ->
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Addr = XAddr bxor Magic,
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dec_addr(1, <<Addr:32>>);
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dec_xor_addr(2, Magic, TrID, <<XAddr:128>>) ->
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Addr = XAddr bxor ((Magic bsl 96) bor TrID),
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dec_addr(2, <<Addr:128>>).
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dec_unknown_attrs(<<Attr:16, Tail/binary>>, Acc) ->
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dec_unknown_attrs(Tail, [Attr|Acc]);
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dec_unknown_attrs(<<>>, Acc) ->
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lists:reverse(Acc).
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enc_attr(_Attr, undefined) ->
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<<>>;
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enc_attr(Attr, Val) ->
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Len = size(Val),
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PaddLen = padd_len(Len),
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<<Attr:16, Len:16, Val/binary, 0:PaddLen>>.
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enc_addr(_Type, undefined) ->
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<<>>;
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enc_addr(Type, {{A1, A2, A3, A4}, Port}) ->
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enc_attr(Type, <<0, 1, Port:16, A1, A2, A3, A4>>);
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enc_addr(Type, {{A1, A2, A3, A4, A5, A6, A7, A8}, Port}) ->
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enc_attr(Type, <<0, 2, Port:16, A1:16, A2:16, A3:16,
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A4:16, A5:16, A6:16, A7:16, A8:16>>).
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enc_xor_addr(_Type, _Magic, _TrID, undefined) ->
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<<>>;
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enc_xor_addr(Type, Magic, _TrID, {{A1, A2, A3, A4}, Port}) ->
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XPort = Port bxor (Magic bsr 16),
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<<Addr:32>> = <<A1, A2, A3, A4>>,
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XAddr = Addr bxor Magic,
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enc_attr(Type, <<0, 1, XPort:16, XAddr:32>>);
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enc_xor_addr(Type, Magic, TrID,
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{{A1, A2, A3, A4, A5, A6, A7, A8}, Port}) ->
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XPort = Port bxor (Magic bsr 16),
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<<Addr:128>> = <<A1:16, A2:16, A3:16, A4:16,
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A5:16, A6:16, A7:16, A8:16>>,
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XAddr = Addr bxor ((Magic bsl 96) bor TrID),
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enc_attr(Type, <<0, 2, XPort:16, XAddr:128>>).
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enc_error_code(undefined) ->
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<<>>;
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enc_error_code({Code, Reason}) ->
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Class = Code div 100,
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Number = Code rem 100,
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enc_attr(?STUN_ATTR_ERROR_CODE,
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<<0:21, Class:3, Number:8, Reason/binary>>).
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enc_unknown_attrs([]) ->
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<<>>;
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enc_unknown_attrs(Attrs) ->
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enc_attr(?STUN_ATTR_UNKNOWN_ATTRIBUTES,
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list_to_binary([<<Attr:16>> || Attr <- Attrs])).
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%%====================================================================
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%% Auxiliary functions
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%%====================================================================
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pp(Tag, N) ->
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try
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pp1(Tag, N)
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catch _:_ ->
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no
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end.
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pp1(stun, N) ->
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N = record_info(size, stun) - 1,
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record_info(fields, stun);
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pp1(_, _) ->
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no.
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%% Workaround for stupid clients.
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-ifdef(NO_PADDING).
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padd_len(_Len) ->
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0.
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-else.
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padd_len(Len) ->
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case Len rem 4 of
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0 -> 0;
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N -> 8*(4-N)
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end.
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-endif.
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%%====================================================================
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%% Test functions
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%%====================================================================
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bind_msg() ->
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Msg = #stun{method = ?STUN_METHOD_BINDING,
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class = request,
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trid = random:uniform(1 bsl 96),
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'SOFTWARE' = <<"test">>},
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encode(Msg).
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test_udp(Addr, Port) ->
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test(Addr, Port, gen_udp).
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test_tcp(Addr, Port) ->
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test(Addr, Port, gen_tcp).
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test_tls(Addr, Port) ->
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test(Addr, Port, ssl).
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test(Addr, Port, Mod) ->
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Res = case Mod of
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gen_udp ->
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Mod:open(0, [binary, {active, false}]);
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_ ->
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Mod:connect(Addr, Port,
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[binary, {active, false}], 1000)
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end,
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case Res of
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{ok, Sock} ->
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if Mod == gen_udp ->
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Mod:send(Sock, Addr, Port, bind_msg());
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true ->
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Mod:send(Sock, bind_msg())
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end,
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case Mod:recv(Sock, 0, 1000) of
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{ok, {_, _, Data}} ->
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try_dec(Data);
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{ok, Data} ->
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try_dec(Data);
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Err ->
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io:format("err: ~p~n", [Err])
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end,
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Mod:close(Sock);
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Err ->
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io:format("err: ~p~n", [Err])
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end.
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try_dec(Data) ->
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case decode(Data) of
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{ok, Msg, _} ->
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io:format("got:~n~s~n", [pp(Msg)]);
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Err ->
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io:format("err: ~p~n", [Err])
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end.
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public_servers() ->
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[{"stun.ekiga.net", 3478, 3478, 5349},
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{"stun.fwdnet.net", 3478, 3478, 5349},
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{"stun.ideasip.com", 3478, 3478, 5349},
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{"stun01.sipphone.com", 3478, 3478, 5349},
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{"stun.softjoys.com", 3478, 3478, 5349},
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{"stun.voipbuster.com", 3478, 3478, 5349},
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{"stun.voxgratia.org", 3478, 3478, 5349},
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{"stun.xten.com", 3478, 3478, 5349},
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{"stunserver.org", 3478, 3478, 5349},
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{"stun.sipgate.net", 10000, 10000, 5349},
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{"numb.viagenie.ca", 3478, 3478, 5349},
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{"stun.ipshka.com", 3478, 3478, 5349},
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{"localhost", 3478, 5349, 5349}].
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test_public() ->
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ssl:start(),
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lists:foreach(
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fun({Addr, UDPPort, TCPPort, TLSPort}) ->
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io:format("trying ~s:~p on UDP... ", [Addr, UDPPort]),
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test_udp(Addr, UDPPort),
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io:format("trying ~s:~p on TCP... ", [Addr, TCPPort]),
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test_tcp(Addr, TCPPort),
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io:format("trying ~s:~p on TLS... ", [Addr, TLSPort]),
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test_tls(Addr, TLSPort)
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end, public_servers()).
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