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
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
use crate::config::*;
use crate::errors::*;
use crate::telemetry::*;
use byteorder::{BigEndian, ByteOrder};
use log::info;
use pnet::packet::udp::{ipv4_checksum, UdpPacket};
use pnet::packet::Packet;
use std::net::{Ipv4Addr, UdpSocket};
use std::ops::Range;
use std::str::FromStr;
use std::sync::{Arc, Mutex};
use std::thread;
use std::time::Duration;
const HEADER_LEN: usize = 8;
const CHKSUM_RNG: Range<usize> = 6..8;
const MAX_SIZE: usize = 65499;
pub type ReadFn<T> = Fn(&T) -> CommsResult<Vec<u8>> + Send + Sync + 'static;
pub type WriteFn<T> = Fn(&T, &[u8]) -> CommsResult<()> + Send + Sync + 'static;
#[derive(Clone)]
pub struct CommsControlBlock<T: Clone> {
pub read: Option<Arc<ReadFn<T>>>,
pub write: Vec<Arc<WriteFn<T>>>,
pub read_conn: T,
pub write_conn: T,
pub handler_port_min: u16,
pub handler_port_max: u16,
pub timeout: u64,
pub ground_ip: Ipv4Addr,
pub satellite_ip: Ipv4Addr,
pub downlink_ports: Option<Vec<u16>>,
pub ground_port: Option<u16>,
}
impl<T: Clone> CommsControlBlock<T> {
pub fn new(
read: Option<Arc<ReadFn<T>>>,
write: Vec<Arc<WriteFn<T>>>,
read_conn: T,
write_conn: T,
config: CommsConfig,
) -> Self {
CommsControlBlock {
read,
write,
read_conn,
write_conn,
handler_port_min: config.handler_port_min.unwrap_or(DEFAULT_HANDLER_START),
handler_port_max: config.handler_port_max.unwrap_or(DEFAULT_HANDLER_END),
timeout: config.timeout.unwrap_or(DEFAULT_TIMEOUT),
ground_ip: Ipv4Addr::from_str(
&config.ground_ip.unwrap_or(DEFAULT_GROUND_IP.to_string()),
)
.unwrap(),
satellite_ip: Ipv4Addr::from_str(
&config
.satellite_ip
.unwrap_or(DEFAULT_SATELLITE_IP.to_string()),
)
.unwrap(),
downlink_ports: config.downlink_ports,
ground_port: config.ground_port,
}
}
}
pub struct CommsService;
impl CommsService {
pub fn start<T: Clone + Send + 'static>(
control: CommsControlBlock<T>,
telem: &Arc<Mutex<CommsTelemetry>>,
) -> CommsResult<()> {
if control.write.is_empty() {
if control.read.is_some() {
let telem_ref = telem.clone();
let control_ref = control.clone();
thread::spawn(move || read_thread(control_ref, &telem_ref));
}
} else {
return Err(CommsServiceError::MissingWriteMethod.into());
}
if let Some(ports) = control.downlink_ports {
if control.write.len() == ports.len() {
for (_, (port, write)) in ports.iter().zip(control.write.iter()).enumerate() {
let telem_ref = telem.clone();
let port_ref = *port;
let conn_ref = control.write_conn.clone();
let write_ref = write.clone();
let ground_ip = control.ground_ip;
let sat_ip = control.satellite_ip;
let ground_port = control
.ground_port
.ok_or(CommsServiceError::MissingGroundPort)?;
thread::spawn(move || {
downlink_endpoint(
&telem_ref,
port_ref,
conn_ref,
&write_ref,
ground_ip,
sat_ip,
ground_port,
);
});
}
} else {
return Err(CommsServiceError::ParameterLengthMismatch.into());
}
}
info!("Communication service started");
Ok(())
}
}
fn read_thread<T: Clone + Send + 'static>(
comms: CommsControlBlock<T>,
data: &Arc<Mutex<CommsTelemetry>>,
) {
let mut port = comms.handler_port_min;
let read = comms.read.unwrap();
loop {
let bytes = match (read)(&comms.read_conn.clone()) {
Ok(bytes) => bytes,
Err(e) => {
log_error(&data, e.to_string()).unwrap();
continue;
}
};
let packet = match UdpPacket::owned(bytes) {
Some(packet) => packet,
None => {
log_telemetry(&data, &TelemType::UpFailed).unwrap();
log_error(&data, CommsServiceError::HeaderParsing.to_string()).unwrap();
error!("Failed to parse packet header");
continue;
}
};
if packet.get_checksum() != ipv4_checksum(&packet, &comms.ground_ip, &comms.satellite_ip) {
log_telemetry(&data, &TelemType::UpFailed).unwrap();
log_error(&data, CommsServiceError::InvalidChecksum.to_string()).unwrap();
error!("Packet checksum failed");
continue;
}
log_telemetry(&data, &TelemType::Up).unwrap();
info!("UDP Packet successfully uplinked");
let socket = match socket_manager(
comms.satellite_ip,
&mut port,
comms.handler_port_min,
comms.handler_port_max,
) {
Some(sock) => sock,
None => {
log_error(&data, CommsServiceError::NoAvailablePorts.to_string()).unwrap();
error!("No message handler ports available");
continue;
}
};
let conn_ref = comms.write_conn.clone();
let write_ref = comms.write[0].clone();
let data_ref = data.clone();
let sat_ref = comms.satellite_ip;
let ground_ref = comms.ground_ip;
let time_ref = comms.timeout;
thread::spawn(move || {
handle_message(
&socket, &data_ref, conn_ref, &write_ref, &packet, time_ref, sat_ref, ground_ref,
);
});
}
}
fn socket_manager(ip: Ipv4Addr, port: &mut u16, min: u16, max: u16) -> Option<UdpSocket> {
let mut socket = None;
let last = *port;
while socket.is_none() {
if *port < max {
*port += 1;
} else {
*port = min;
}
socket = UdpSocket::bind((ip, *port)).ok();
if last == *port {
break;
}
}
socket
}
fn handle_message<T: Clone>(
socket: &UdpSocket,
data: &Arc<Mutex<CommsTelemetry>>,
write_conn: T,
write: &Arc<WriteFn<T>>,
message: &UdpPacket,
timeout: u64,
sat_ip: Ipv4Addr,
ground_ip: Ipv4Addr,
) {
let mut buf = [0; MAX_SIZE];
match socket.set_read_timeout(Some(Duration::from_millis(timeout))) {
Ok(_) => (),
Err(e) => return log_error(&data, e.to_string()).unwrap(),
};
match socket.send_to(message.payload(), (sat_ip, message.get_destination())) {
Ok(_) => (),
Err(e) => return log_error(&data, e.to_string()).unwrap(),
};
info!("UDP Packet sent to port {}", message.get_destination());
let (size, _) = match socket.recv_from(&mut buf) {
Ok(tuple) => tuple,
Err(e) => return log_error(&data, e.to_string()).unwrap(),
};
let packet = match build_packet(
&buf[0..size],
message.get_destination(),
message.get_source(),
(size + HEADER_LEN) as u16,
sat_ip,
ground_ip,
) {
Ok(packet) => packet,
Err(e) => return log_error(&data, e.to_string()).unwrap(),
};
match write(&write_conn.clone(), packet.as_slice()) {
Ok(_) => {
log_telemetry(&data, &TelemType::Down).unwrap();
info!("UDP Packet successfully downlinked");
}
Err(e) => {
log_telemetry(&data, &TelemType::DownFailed).unwrap();
log_error(&data, e.to_string()).unwrap();
error!("UDP packet failed to downlink");
}
};
}
fn downlink_endpoint<T: Clone>(
data: &Arc<Mutex<CommsTelemetry>>,
port: u16,
write_conn: T,
write: &Arc<WriteFn<T>>,
ground_ip: Ipv4Addr,
sat_ip: Ipv4Addr,
ground_port: u16,
) {
let socket = match UdpSocket::bind((sat_ip, port)) {
Ok(sock) => sock,
Err(e) => return log_error(&data, e.to_string()).unwrap(),
};
loop {
let mut buf = [0; MAX_SIZE];
let (size, address) = match socket.recv_from(&mut buf) {
Ok(tuple) => tuple,
Err(e) => {
log_error(&data, e.to_string()).unwrap();
continue;
}
};
let packet = match build_packet(
&buf[0..size],
address.port(),
ground_port,
(size + HEADER_LEN) as u16,
sat_ip,
ground_ip,
) {
Ok(packet) => packet,
Err(e) => {
log_error(&data, e.to_string()).unwrap();
continue;
}
};
match write(&write_conn.clone(), packet.as_slice()) {
Ok(_) => {
log_telemetry(&data, &TelemType::Down).unwrap();
info!("UDP Packet successfully downlinked");
}
Err(e) => {
log_telemetry(&data, &TelemType::DownFailed).unwrap();
log_error(&data, e.to_string()).unwrap();
error!("UDP Packet failed to downlink");
}
};
}
}
fn build_packet(
payload: &[u8],
source: u16,
dest: u16,
length: u16,
sat: Ipv4Addr,
ground: Ipv4Addr,
) -> CommsResult<Vec<u8>> {
let mut header = [0; HEADER_LEN];
let fields = [source, dest, length, 0];
BigEndian::write_u16_into(&fields, &mut header);
let mut packet = header.to_vec();
packet.append(&mut payload.to_vec());
let packet_without_checksum = match UdpPacket::owned(packet.clone()) {
Some(bytes) => bytes,
None => return Err(CommsServiceError::HeaderParsing.into()),
};
let mut checksum = [0; 2];
BigEndian::write_u16(
&mut checksum,
ipv4_checksum(&packet_without_checksum, &sat, &ground),
);
packet.splice(CHKSUM_RNG, checksum.iter().cloned());
Ok(packet)
}