1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2005-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%%
%%% Description : SSH 1/2 pdu elements encode/decode
-module(ssh_bits).
-include("ssh.hrl").
-export([mpint/1, name_list/1]).
-export([random/1]).
%%%----------------------------------------------------------------
name_list(NamesList) -> list_to_binary(lists:join($,, NamesList)).
%%%----------------------------------------------------------------
%%% Multi Precision Integer encoding
mpint(-1) -> <<0,0,0,1,16#ff>>;
mpint(0) -> <<0,0,0,0>>;
mpint(X) when X < 0 -> mpint_neg(X,0,[]);
mpint(X) -> mpint_pos(X,0,[]).
mpint_neg(-1,I,Ds=[MSB|_]) ->
if MSB band 16#80 =/= 16#80 ->
<<?UINT32((I+1)), (list_to_binary([255|Ds]))/binary>>;
true ->
<<?UINT32(I), (list_to_binary(Ds))/binary>>
end;
mpint_neg(X,I,Ds) ->
mpint_neg(X bsr 8,I+1,[(X band 255)|Ds]).
mpint_pos(0,I,Ds=[MSB|_]) ->
if MSB band 16#80 == 16#80 ->
<<?UINT32((I+1)), (list_to_binary([0|Ds]))/binary>>;
true ->
<<?UINT32(I), (list_to_binary(Ds))/binary>>
end;
mpint_pos(X,I,Ds) ->
mpint_pos(X bsr 8,I+1,[(X band 255)|Ds]).
%%%----------------------------------------------------------------
%% random/1
%% Generate N random bytes
%%
random(N) -> crypto:strong_rand_bytes(N).
|
