/
udh.ex
192 lines (149 loc) · 5.75 KB
/
udh.ex
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
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
defmodule SMPPEX.Pdu.UDH do
@moduledoc """
Module for parsing encoded IEs from UDHs.
"""
alias SMPPEX.Pdu
import Bitwise
@esm_class_gsm_udhi 0b01000000
@error_invalid_udh_data "Invalid UDH data"
@error_invalid_udh_length "Invalid UDH length"
@error_invalid_udh_ie_length "Invalid UDH IE length"
@error_invalid_udh_ie_id "Invalid UDH IE id"
@error_invalid_udh_ie_data "Invalid UDH IE data"
@error_invalid_message_data "Invalid Message data"
@error_udh_data_too_long "UDH is too long"
@spec has_udh?(pdu :: Pdu.t()) :: boolean
@doc """
Checks if message in PDU has UDH (by inspecting `esm_class` field).
## Example
iex> pdu = SMPPEX.Pdu.new({1,0,1}, %{esm_class: 0}, %{})
iex> SMPPEX.Pdu.UDH.has_udh?(pdu)
false
iex> pdu = SMPPEX.Pdu.new({1,0,1}, %{esm_class: 0b01000000}, %{})
iex> SMPPEX.Pdu.UDH.has_udh?(pdu)
true
"""
def has_udh?(pdu) do
case Pdu.field(pdu, :esm_class) do
nil -> false
esm_class -> has_udh_flag?(esm_class)
end
end
defp has_udh_flag?(esm_class) do
esm_class && (esm_class &&& @esm_class_gsm_udhi) == @esm_class_gsm_udhi
end
@type ie :: {byte, binary}
@spec extract(message :: binary) :: {:error, term} | {:ok, list(ie), binary}
@doc """
Extracts list of IEs from UDH.
Returns one of the following
* `{:ok, ies, message}` where `ies` is a list of IE tuples `{id, value}` and `message`
is the original message without UDH;
* `{:error, reason}` in case of errors.
## Example
iex> data = <<5, 0, 3, 197, 3, 3, "message">>
iex> SMPPEX.Pdu.UDH.extract(data)
{:ok, [{0, <<197, 3, 3>>}], "message"}
iex> data = <<0x0B, 0x05, 0x04, 0x06, 0x2d, 0x00, 0x00, 0x00, 0x03, 0x01, 0x02, 0x01, "message">>
iex> SMPPEX.Pdu.UDH.extract(data)
{:ok, [{0x05, <<0x06, 0x2d, 0x00, 0x00>>}, {0x00, <<0x01, 0x02, 0x01>>}], "message"}
iex> data = <<0x10, "short">>
iex> SMPPEX.Pdu.UDH.extract(data)
{:error, "#{@error_invalid_udh_length}"}
iex> data = <<0x06, 0x00, 0x03, 0x01, 0x02, 0x01, "message">>
iex> SMPPEX.Pdu.UDH.extract(data)
{:error, "#{@error_invalid_udh_data}"}
iex> data = <<5, 0, 4, 197, 3, 3, "message">>
iex> SMPPEX.Pdu.UDH.extract(data)
{:error, "#{@error_invalid_udh_ie_length}"}
"""
def extract(data) do
case data do
<<udh_length::integer-unsigned-size(8), rest::binary>> ->
case rest do
<<ies_data::binary-size(udh_length), message::binary>> ->
parse_ies(ies_data, message)
_ ->
{:error, @error_invalid_udh_length}
end
_ ->
{:error, @error_invalid_udh_data}
end
end
defp parse_ies(ies_data, message) do
case parse_ies_data(ies_data, []) do
{:ok, ies} -> {:ok, ies, message}
{:error, _} = err -> err
end
end
defp parse_ies_data(<<>>, parsed), do: {:ok, Enum.reverse(parsed)}
defp parse_ies_data(
<<
ie_id::integer-unsigned-size(8),
ie_len::integer-unsigned-size(8),
ie_data_and_rest::binary
>>,
parsed
) do
case ie_data_and_rest do
<<ie_data::binary-size(ie_len), rest::binary>> ->
parse_ies_data(rest, [{ie_id, ie_data} | parsed])
_ ->
{:error, @error_invalid_udh_ie_length}
end
end
defp parse_ies_data(_, _), do: {:error, @error_invalid_udh_data}
@spec add(list(ie), binary) :: {:ok, binary} | {:error, any}
@doc """
Encodes IEs and prepends message with the encoded value.
The result is one of the following:
* `{:ok, message}` where message is the original message prefixed with UDH;
* `{:error, reason}` in case of errors.
## Example
iex> ies = [{0x05, <<0x06, 0x2d, 0x00, 0x00>>}, {0x00, <<0x01, 0x02, 0x01>>}]
iex> SMPPEX.Pdu.UDH.add(ies, "message")
{:ok, <<0x0B, 0x05, 0x04, 0x06, 0x2d, 0x00, 0x00, 0x00, 0x03, 0x01, 0x02, 0x01, "message">>}
iex> ies = [{0, 123}]
iex> SMPPEX.Pdu.UDH.add(ies, "message")
{:error, "#{@error_invalid_udh_ie_data}"}
iex> ies = [{345, "ie"}]
iex> SMPPEX.Pdu.UDH.add(ies, "message")
{:error, "#{@error_invalid_udh_ie_id}"}
iex> ies = [{-1, "ie"}]
iex> SMPPEX.Pdu.UDH.add(ies, "message")
{:error, "#{@error_invalid_udh_ie_id}"}
iex> ies = [{0, <<1 :: integer-size(2040)>>}]
iex> SMPPEX.Pdu.UDH.add(ies, "message")
{:error, "#{@error_udh_data_too_long}"}
"""
def add(ies, message) do
case pack_ies(ies, []) do
{:ok, data} -> concat_ie_data_and_message(data, message)
{:error, _} = err -> err
end
end
defp pack_ies([], packed), do: {:ok, packed |> Enum.reverse() |> Enum.join()}
defp pack_ies([ie | ies], packed) do
case pack_ie(ie) do
{:ok, packed_ie} -> pack_ies(ies, [packed_ie | packed])
{:error, _} = err -> err
end
end
defp pack_ie({id, _}) when not is_integer(id), do: {:error, @error_invalid_udh_ie_id}
defp pack_ie({id, _}) when id < 0x00 or id > 0xFF, do: {:error, @error_invalid_udh_ie_id}
defp pack_ie({_, value}) when not is_binary(value), do: {:error, @error_invalid_udh_ie_data}
defp pack_ie({_, value}) when byte_size(value) > 0xFF, do: {:error, @error_invalid_udh_ie_data}
defp pack_ie({id, value}) do
len = byte_size(value)
packed_ie = <<id::integer-unsigned-size(8), len::integer-unsigned-size(8), value::binary>>
{:ok, packed_ie}
end
defp concat_ie_data_and_message(_data, message) when not is_binary(message),
do: {:error, @error_invalid_message_data}
defp concat_ie_data_and_message(data, _message) when byte_size(data) > 0xFF,
do: {:error, @error_udh_data_too_long}
defp concat_ie_data_and_message(data, message) do
data_len = byte_size(data)
{:ok, <<data_len::integer-unsigned-size(8), data::binary, message::binary>>}
end
end