AX.25 Amateur Radio Link-Layer Protocol
irmin: consistent naming — Backend.S has type t, phantom tag is B.t
+130
-93
+17
-4
lib/ax25.ml
+17
-4
lib/ax25.ml
···
345
345
346
346
(* {1 Encoding/Decoding} *)
347
347
348
-
let encode_address_to_bytes addr =
348
+
(** Determine whether a control field is a command (vs response). AX.25 2.2
349
+
Section 6.1.2: UI, SABM, DISC are always commands; UA, DM, FRMR are
350
+
responses; I/S frames default to command. *)
351
+
let is_command = function
352
+
| UI | SABM | DISC -> true
353
+
| UA | DM | FRMR -> false
354
+
| I _ | RR _ | RNR _ | REJ _ | Unknown _ -> true
355
+
356
+
let encode_address_to_bytes ~control addr =
349
357
let all =
350
358
let n_digis = List.length addr.digipeaters in
351
359
let no_digis = n_digis = 0 in
360
+
(* AX.25 2.2 Section 6.1.2: command = dst C=1, src C=0;
361
+
response = dst C=0, src C=1. Digipeater H bit = has_been_repeated. *)
362
+
let cmd = is_command control in
352
363
let dst =
353
364
callsign_wire_of_callsign addr.destination ~is_last:false
354
-
~has_been_repeated:false
365
+
~has_been_repeated:cmd
355
366
in
356
367
let src =
357
368
callsign_wire_of_callsign addr.source ~is_last:no_digis
358
-
~has_been_repeated:false
369
+
~has_been_repeated:(not cmd)
359
370
in
360
371
let digis =
361
372
List.mapi
···
398
409
let write_to_buf frame =
399
410
let buf = Buffer.create 512 in
400
411
(* Address field *)
401
-
let addr_bytes = encode_address_to_bytes frame.address in
412
+
let addr_bytes =
413
+
encode_address_to_bytes ~control:frame.control frame.address
414
+
in
402
415
Buffer.add_bytes buf addr_bytes;
403
416
(* Control *)
404
417
let ctrl_buf = Wire.encode_to_bytes control_typ frame.control in
+1
-1
test/interop/pyax25/dune
+1
-1
test/interop/pyax25/dune
+5
test/interop/pyax25/scripts/generate.py
+5
test/interop/pyax25/scripts/generate.py
···
44
44
45
45
# Basic UI frame, no digipeaters
46
46
f = AX25UnnumberedInformationFrame(
47
+
cr=True,
47
48
destination=addr("CQ"),
48
49
source=addr("N0CALL", 1),
49
50
pid=0xF0,
···
56
57
57
58
# UI frame with digipeater
58
59
f = AX25UnnumberedInformationFrame(
60
+
cr=True,
59
61
destination=addr("W1AW"),
60
62
source=addr("N0CALL"),
61
63
repeaters=[AX25Address.decode("RELAY").normalised],
···
69
71
70
72
# NJ7P > N7LEM — spec example
71
73
f = AX25UnnumberedInformationFrame(
74
+
cr=True,
72
75
destination=addr("NJ7P"),
73
76
source=addr("N7LEM"),
74
77
pid=0xF0,
···
79
82
80
83
# Source SSID=0, no digis — the regression case
81
84
f = AX25UnnumberedInformationFrame(
85
+
cr=True,
82
86
destination=addr("BEACON"),
83
87
source=addr("TEST"),
84
88
pid=0xF0,
···
89
93
90
94
# IP over AX.25
91
95
f = AX25UnnumberedInformationFrame(
96
+
cr=True,
92
97
destination=addr("CQ"),
93
98
source=addr("N0CALL"),
94
99
pid=0xCC,
+107
-88
test/interop/pyax25/test.ml
+107
-88
test/interop/pyax25/test.ml
···
5
5
6
6
let trace path = Filename.concat "traces" path
7
7
8
-
let strip_cr s =
9
-
if String.length s > 0 && s.[String.length s - 1] = '\r' then
10
-
String.sub s 0 (String.length s - 1)
11
-
else s
8
+
(* {1 Trace Row Types} *)
9
+
10
+
type ui_frame_row = {
11
+
name : string;
12
+
source : string;
13
+
destination : string;
14
+
digipeaters : string;
15
+
pid_hex : string;
16
+
info_hex : string;
17
+
frame_hex : string;
18
+
}
12
19
13
-
let read_csv path =
14
-
let ic = open_in (trace path) in
15
-
let _header = input_line ic in
16
-
let rows = ref [] in
17
-
(try
18
-
while true do
19
-
let line = strip_cr (input_line ic) in
20
-
if String.length line > 0 && line.[0] <> '#' then
21
-
rows := String.split_on_char ',' line :: !rows
22
-
done
23
-
with End_of_file -> ());
24
-
close_in ic;
25
-
List.rev !rows
20
+
let ui_frame_codec =
21
+
Csvt.(
22
+
Row.(
23
+
obj (fun name source destination digipeaters pid_hex info_hex frame_hex ->
24
+
{
25
+
name;
26
+
source;
27
+
destination;
28
+
digipeaters;
29
+
pid_hex;
30
+
info_hex;
31
+
frame_hex;
32
+
})
33
+
|> col "name" string ~enc:(fun r -> r.name)
34
+
|> col "source" string ~enc:(fun r -> r.source)
35
+
|> col "destination" string ~enc:(fun r -> r.destination)
36
+
|> col "digipeaters" string ~enc:(fun r -> r.digipeaters)
37
+
|> col "pid_hex" string ~enc:(fun r -> r.pid_hex)
38
+
|> col "info_hex" string ~enc:(fun r -> r.info_hex)
39
+
|> col "frame_hex" string ~enc:(fun r -> r.frame_hex)
40
+
|> finish))
41
+
42
+
type ext_bit_row = {
43
+
name : string;
44
+
frame_hex : string;
45
+
n_callsigns : int;
46
+
last_index : int;
47
+
}
48
+
49
+
let ext_bit_codec =
50
+
Csvt.(
51
+
Row.(
52
+
obj (fun name frame_hex n_callsigns last_index ->
53
+
{ name; frame_hex; n_callsigns; last_index })
54
+
|> col "name" string ~enc:(fun r -> r.name)
55
+
|> col "frame_hex" string ~enc:(fun r -> r.frame_hex)
56
+
|> col "n_callsigns" int ~enc:(fun r -> r.n_callsigns)
57
+
|> col "last_index" int ~enc:(fun r -> r.last_index)
58
+
|> finish))
59
+
60
+
(* {1 Helpers} *)
26
61
27
62
let hex_to_bytes hex =
28
63
let len = String.length hex / 2 in
···
51
86
(* {1 UI Frame Interop Tests} *)
52
87
53
88
let test_ui_frame_encoding () =
54
-
let rows = read_csv "ui_frames.csv" in
89
+
let rows =
90
+
match Csvt.decode_file ui_frame_codec (trace "ui_frames.csv") with
91
+
| Ok rows -> rows
92
+
| Error e -> Alcotest.failf "CSV decode: %a" Csvt.pp_error e
93
+
in
55
94
List.iter
56
-
(fun row ->
57
-
match row with
58
-
| [ name; src_str; dst_str; _digis; _pid_hex; _info_hex; frame_hex ] -> (
59
-
(* Build the frame with our implementation *)
60
-
let src = Ax25.callsign_of_string src_str in
61
-
let dst = Ax25.callsign_of_string dst_str in
62
-
match (src, dst) with
63
-
| Some _src, Some _dst -> (
64
-
let ref_bytes = hex_to_bytes frame_hex in
65
-
(* Our decoder must successfully parse frames from aioax25 *)
66
-
match Ax25.decode ref_bytes with
67
-
| Ok frame -> (
68
-
(* Verify decoded addresses match the trace metadata *)
69
-
Alcotest.(check string)
70
-
(name ^ " src") src_str
71
-
(Ax25.string_of_callsign frame.address.source);
72
-
Alcotest.(check string)
73
-
(name ^ " dst") dst_str
74
-
(Ax25.string_of_callsign frame.address.destination);
75
-
(* Re-encode and verify the frame is parseable *)
76
-
let our_bytes = Ax25.encode frame in
77
-
match Ax25.decode our_bytes with
78
-
| Ok frame2 ->
79
-
Alcotest.(check string)
80
-
(name ^ " re-decode src")
81
-
(Ax25.string_of_callsign frame.address.source)
82
-
(Ax25.string_of_callsign frame2.address.source)
83
-
| Error e ->
84
-
Alcotest.failf "%s: re-decode failed: %a" name
85
-
Ax25.pp_error e)
86
-
| Error e ->
87
-
Alcotest.failf "%s: failed to decode reference frame: %a" name
88
-
Ax25.pp_error e)
89
-
| _ -> Alcotest.failf "%s: bad callsign in trace" name)
90
-
| _ -> Alcotest.failf "bad CSV row: %d fields" (List.length row))
95
+
(fun (r : ui_frame_row) ->
96
+
let ref_bytes = hex_to_bytes r.frame_hex in
97
+
(* Our decoder must successfully parse frames from aioax25 *)
98
+
match Ax25.decode ref_bytes with
99
+
| Ok frame ->
100
+
Alcotest.(check string)
101
+
(r.name ^ " src") r.source
102
+
(Ax25.string_of_callsign frame.address.source);
103
+
Alcotest.(check string)
104
+
(r.name ^ " dst") r.destination
105
+
(Ax25.string_of_callsign frame.address.destination);
106
+
(* Re-encode and compare bytes exactly against aioax25 *)
107
+
let our_bytes = Ax25.encode frame in
108
+
Alcotest.(check string)
109
+
(r.name ^ " exact bytes") r.frame_hex (bytes_to_hex our_bytes)
110
+
| Error e ->
111
+
Alcotest.failf "%s: failed to decode reference frame: %a" r.name
112
+
Ax25.pp_error e)
91
113
rows
92
114
93
115
(* {1 Extension Bit Interop Tests} *)
94
116
95
117
let test_extension_bits () =
96
-
let rows = read_csv "extension_bits.csv" in
118
+
let rows =
119
+
match Csvt.decode_file ext_bit_codec (trace "extension_bits.csv") with
120
+
| Ok rows -> rows
121
+
| Error e -> Alcotest.failf "CSV decode: %a" Csvt.pp_error e
122
+
in
97
123
List.iter
98
-
(fun row ->
99
-
match row with
100
-
| [ name; frame_hex; n_str; last_str ] -> (
101
-
let n_callsigns = int_of_string n_str in
102
-
let last_index = int_of_string last_str in
103
-
let frame_bytes = hex_to_bytes frame_hex in
104
-
(* Check extension bits in the raw reference bytes *)
105
-
for i = 0 to n_callsigns - 1 do
124
+
(fun (r : ext_bit_row) ->
125
+
let frame_bytes = hex_to_bytes r.frame_hex in
126
+
(* Check extension bits in the raw reference bytes *)
127
+
for i = 0 to r.n_callsigns - 1 do
128
+
let ssid_off = (i * 7) + 6 in
129
+
let ext = Bytes.get_uint8 frame_bytes ssid_off land 0x01 in
130
+
if i = r.last_index then
131
+
Alcotest.(check int)
132
+
(Printf.sprintf "%s: callsign %d ext=1 (last)" r.name i)
133
+
1 ext
134
+
else
135
+
Alcotest.(check int)
136
+
(Printf.sprintf "%s: callsign %d ext=0" r.name i)
137
+
0 ext
138
+
done;
139
+
(* Decode with our implementation and re-encode *)
140
+
match Ax25.decode frame_bytes with
141
+
| Ok frame ->
142
+
let our_bytes = Ax25.encode frame in
143
+
for i = 0 to r.n_callsigns - 1 do
106
144
let ssid_off = (i * 7) + 6 in
107
-
let ext = Bytes.get_uint8 frame_bytes ssid_off land 0x01 in
108
-
if i = last_index then
109
-
Alcotest.(check int)
110
-
(Printf.sprintf "%s: callsign %d ext=1 (last)" name i)
111
-
1 ext
112
-
else
113
-
Alcotest.(check int)
114
-
(Printf.sprintf "%s: callsign %d ext=0" name i)
115
-
0 ext
116
-
done;
117
-
(* Decode with our implementation and re-encode *)
118
-
match Ax25.decode frame_bytes with
119
-
| Ok frame ->
120
-
let our_bytes = Ax25.encode frame in
121
-
(* Our encoded bytes include FCS; strip it for address comparison *)
122
-
for i = 0 to n_callsigns - 1 do
123
-
let ssid_off = (i * 7) + 6 in
124
-
let our_ext = Bytes.get_uint8 our_bytes ssid_off land 0x01 in
125
-
let ref_ext = Bytes.get_uint8 frame_bytes ssid_off land 0x01 in
126
-
Alcotest.(check int)
127
-
(Printf.sprintf "%s: our ext[%d] matches ref" name i)
128
-
ref_ext our_ext
129
-
done
130
-
| Error e ->
131
-
Alcotest.failf "%s: decode failed: %a" name Ax25.pp_error e)
132
-
| _ -> Alcotest.failf "bad CSV row")
145
+
let our_ext = Bytes.get_uint8 our_bytes ssid_off land 0x01 in
146
+
let ref_ext = Bytes.get_uint8 frame_bytes ssid_off land 0x01 in
147
+
Alcotest.(check int)
148
+
(Printf.sprintf "%s: our ext[%d] matches ref" r.name i)
149
+
ref_ext our_ext
150
+
done
151
+
| Error e -> Alcotest.failf "%s: decode failed: %a" r.name Ax25.pp_error e)
133
152
rows
134
153
135
154
let () =