%%%----------------------------------------------------------------------
%%% File    : mod_proxy65_lib.erl
%%% Author  : Evgeniy Khramtsov <xram@jabber.ru>
%%% Purpose : SOCKS5 parsing library.
%%% Created : 12 Oct 2006 by Evgeniy Khramtsov <xram@jabber.ru>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2022   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.,
%%% 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
%%%
%%%----------------------------------------------------------------------

-module(mod_proxy65_lib).

-author('xram@jabber.ru').

-include("mod_proxy65.hrl").

-export([unpack_init_message/1, unpack_auth_request/1,
	 unpack_request/1, make_init_reply/1, make_auth_reply/1,
	 make_reply/1, make_error_reply/1, make_error_reply/2]).

unpack_init_message(<<(?VERSION_5), N,
		      AuthMethodList:N/binary>>)
    when N > 0, N < 256 ->
    {ok, binary_to_list(AuthMethodList)};
unpack_init_message(_) -> error.

unpack_auth_request(<<1, ULen, User:ULen/binary, PLen,
		      Pass:PLen/binary>>)
    when ULen < 256, PLen < 256 ->
    {(User), (Pass)};
unpack_auth_request(_) -> error.

unpack_request(<<(?VERSION_5), CMD, RSV,
		 (?ATYP_DOMAINNAME), 40, SHA1:40/binary, 0, 0>>)
    when CMD == (?CMD_CONNECT); CMD == (?CMD_UDP) ->
    Command = if CMD == (?CMD_CONNECT) -> connect;
		 CMD == (?CMD_UDP) -> udp
	      end,
    #s5_request{cmd = Command, rsv = RSV, sha1 = (SHA1)};
unpack_request(_) -> error.

make_init_reply(Method) -> [?VERSION_5, Method].

make_auth_reply(true) -> [1, ?SUCCESS];
make_auth_reply(false) -> [1, ?ERR_NOT_ALLOWED].

make_reply(#s5_request{rsv = RSV, sha1 = SHA1}) ->
    [?VERSION_5, ?SUCCESS, RSV, ?ATYP_DOMAINNAME,
     byte_size(SHA1), SHA1, 0, 0].

make_error_reply(Request) ->
    make_error_reply(Request, ?ERR_NOT_ALLOWED).

make_error_reply(#s5_request{rsv = RSV, sha1 = SHA1},
		 Reason) ->
    [?VERSION_5, Reason, RSV, ?ATYP_DOMAINNAME,
     byte_size(SHA1), SHA1, 0, 0].