code.octet-stream.net Git - m17rt/blob - m17app/src/app.rs

   1 use crate::adapter::{PacketAdapter, StreamAdapter};
   2 use crate::tnc::Tnc;
   3 use m17core::kiss::{KissBuffer, KissCommand, KissFrame};
   4 use m17core::protocol::{EncryptionType, LsfFrame, PacketType, StreamFrame};
   5
   6 use log::debug;
   7 use std::collections::HashMap;
   8 use std::sync::mpsc;
   9 use std::sync::{Arc, RwLock};
  10
  11 pub struct M17App {
  12     adapters: Arc<RwLock<Adapters>>,
  13     event_tx: mpsc::SyncSender<TncControlEvent>,
  14 }
  15
  16 impl M17App {
  17     pub fn new<T: Tnc + Send + 'static>(mut tnc: T) -> Self {
  18         let write_tnc = tnc.try_clone().unwrap();
  19         let (event_tx, event_rx) = mpsc::sync_channel(128);
  20         let listeners = Arc::new(RwLock::new(Adapters::new()));
  21         spawn_reader(tnc, listeners.clone());
  22         spawn_writer(write_tnc, event_rx);
  23         Self {
  24             adapters: listeners,
  25             event_tx,
  26         }
  27     }
  28
  29     pub fn add_packet_adapter<P: PacketAdapter + 'static>(&self, adapter: P) -> usize {
  30         let adapter = Arc::new(adapter);
  31         let mut adapters = self.adapters.write().unwrap();
  32         let id = adapters.next;
  33         adapters.next += 1;
  34         adapters.packet.insert(id, adapter.clone());
  35         drop(adapters);
  36         adapter.adapter_registered(id, self.tx());
  37         id
  38     }
  39
  40     pub fn add_stream_adapter<S: StreamAdapter + 'static>(&self, adapter: S) -> usize {
  41         let adapter = Arc::new(adapter);
  42         let mut adapters = self.adapters.write().unwrap();
  43         let id = adapters.next;
  44         adapters.next += 1;
  45         adapters.stream.insert(id, adapter.clone());
  46         drop(adapters);
  47         adapter.adapter_registered(id, self.tx());
  48         id
  49     }
  50
  51     pub fn remove_packet_adapter(&self, id: usize) {
  52         if let Some(a) = self.adapters.write().unwrap().packet.remove(&id) {
  53             a.adapter_removed();
  54         }
  55     }
  56
  57     pub fn remove_stream_adapter(&self, id: usize) {
  58         if let Some(a) = self.adapters.write().unwrap().stream.remove(&id) {
  59             a.adapter_removed();
  60         }
  61     }
  62
  63     /// Create a handle that can be used to transmit data on the TNC
  64     pub fn tx(&self) -> TxHandle {
  65         TxHandle {
  66             event_tx: self.event_tx.clone(),
  67         }
  68     }
  69
  70     pub fn start(&self) {
  71         let _ = self.event_tx.send(TncControlEvent::Start);
  72     }
  73
  74     pub fn close(&self) {
  75         let _ = self.event_tx.send(TncControlEvent::Close);
  76     }
  77 }
  78
  79 pub struct TxHandle {
  80     event_tx: mpsc::SyncSender<TncControlEvent>,
  81 }
  82
  83 impl TxHandle {
  84     pub fn transmit_packet(&self, packet_type: PacketType, payload: &[u8]) {
  85         // hang on where do we get the LSF details from? We need a destination obviously
  86         // our source address needs to be configured here too
  87         // also there is possible CAN, encryption, meta payload
  88
  89         // we will immediately convert this into a KISS payload before sending into channel so we only need borrow on data
  90     }
  91
  92     // add more methods here for stream outgoing
  93
  94     pub fn transmit_stream_start(&self, lsf: LsfFrame) {
  95         // TODO: is asking for an LsfFrame a good idea or unfriendly API?
  96         // What I should do here is create a LinkSetup struct which wraps an LsfFrame and can be loaded with a raw one
  97         let kiss_frame = KissFrame::new_stream_setup(&lsf.0).unwrap();
  98         let _ = self.event_tx.send(TncControlEvent::Kiss(kiss_frame));
  99     }
 100
 101     // as long as there is only one TNC it is implied there is only ever one stream transmission in flight
 102
 103     pub fn transmit_stream_next(&self, stream: StreamFrame) {
 104         let kiss_frame = KissFrame::new_stream_data(&stream).unwrap();
 105         let _ = self.event_tx.send(TncControlEvent::Kiss(kiss_frame));
 106     }
 107 }
 108
 109 /// Synchronised structure for listeners subscribing to packets and streams.
 110 ///
 111 /// Each listener will be notified in turn of each event.
 112 struct Adapters {
 113     /// Identifier to be assigned to the next listener, starting from 0
 114     next: usize,
 115     packet: HashMap<usize, Arc<dyn PacketAdapter>>,
 116     stream: HashMap<usize, Arc<dyn StreamAdapter>>,
 117 }
 118
 119 impl Adapters {
 120     fn new() -> Self {
 121         Self {
 122             next: 0,
 123             packet: HashMap::new(),
 124             stream: HashMap::new(),
 125         }
 126     }
 127 }
 128
 129 /// Carries a request from a method on M17App to the TNC's writer thread, which will execute it.
 130 enum TncControlEvent {
 131     Kiss(KissFrame),
 132     Start,
 133     Close,
 134 }
 135
 136 fn spawn_reader<T: Tnc>(mut tnc: T, adapters: Arc<RwLock<Adapters>>) {
 137     std::thread::spawn(move || {
 138         let mut kiss_buffer = KissBuffer::new();
 139         let mut stream_running = false;
 140         loop {
 141             let mut buf = kiss_buffer.buf_remaining();
 142             let n = match tnc.read(&mut buf) {
 143                 Ok(n) => n,
 144                 Err(_) => break,
 145             };
 146             kiss_buffer.did_write(n);
 147             while let Some(frame) = kiss_buffer.next_frame() {
 148                 if frame.command() != Ok(KissCommand::DataFrame) {
 149                     continue;
 150                 }
 151                 match frame.port() {
 152                     Ok(m17core::kiss::PORT_PACKET_BASIC) => {
 153                         // no action
 154                         // we will handle the more full-featured version from from port 1
 155                     }
 156                     Ok(m17core::kiss::PORT_PACKET_FULL) => {
 157                         let mut payload = [0u8; 855]; // 30 byte LSF + 825 byte packet including CRC
 158                         let Ok(n) = frame.decode_payload(&mut payload) else {
 159                             debug!("failed to decode payload from KISS frame");
 160                             continue;
 161                         };
 162                         if n < 33 {
 163                             debug!("unusually short full packet frame");
 164                             continue;
 165                         }
 166                         let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 167                         if lsf.check_crc() != 0 {
 168                             debug!("LSF in full packet frame did not pass CRC");
 169                             continue;
 170                         }
 171                         if lsf.encryption_type() != EncryptionType::None {
 172                             debug!("we only understand None encryption for now - skipping packet");
 173                             continue;
 174                         }
 175                         let Some((packet_type, type_len)) = PacketType::from_proto(&payload[30..n])
 176                         else {
 177                             debug!("failed to decode packet type");
 178                             continue;
 179                         };
 180                         if (n - 30 - type_len) < 2 {
 181                             debug!("packet payload too small to provide CRC");
 182                             continue;
 183                         }
 184                         let packet_crc = m17core::crc::m17_crc(&payload[30..n]);
 185                         if packet_crc != 0 {
 186                             debug!("packet CRC does not pass");
 187                             continue;
 188                         }
 189                         let packet_payload: Arc<[u8]> =
 190                             Arc::from(&payload[(30 + type_len)..(n - 2)]);
 191
 192                         let subs: Vec<_> =
 193                             adapters.read().unwrap().packet.values().cloned().collect();
 194                         for s in subs {
 195                             s.packet_received(
 196                                 lsf.clone(),
 197                                 packet_type.clone(),
 198                                 packet_payload.clone(),
 199                             );
 200                         }
 201                     }
 202                     Ok(m17core::kiss::PORT_STREAM) => {
 203                         let mut payload = [0u8; 32];
 204                         let Ok(n) = frame.decode_payload(&mut payload) else {
 205                             debug!("failed to decode stream payload from KISS frame");
 206                             continue;
 207                         };
 208                         if n == 30 {
 209                             let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 210                             if lsf.check_crc() != 0 {
 211                                 debug!("initial LSF in stream did not pass CRC");
 212                                 continue;
 213                             }
 214                             stream_running = true;
 215                             let subs: Vec<_> =
 216                                 adapters.read().unwrap().stream.values().cloned().collect();
 217                             for s in subs {
 218                                 s.stream_began(lsf.clone());
 219                             }
 220                         } else if n == 26 {
 221                             if !stream_running {
 222                                 debug!("ignoring stream data as we didn't get a valid LSF first");
 223                                 continue;
 224                             }
 225                             // TODO: parse LICH and handle the different changing subvalues META could have
 226                             if m17core::crc::m17_crc(&payload[6..n]) != 0 {
 227                                 debug!("stream data CRC mismatch");
 228                                 continue;
 229                             }
 230                             let mut frame_number = u16::from_be_bytes([payload[6], payload[7]]);
 231                             let is_final = (frame_number & 0x8000) > 0;
 232                             frame_number &= 0x7fff;
 233                             let data: [u8; 16] = payload[8..24].try_into().unwrap();
 234                             let data = Arc::new(data);
 235                             if is_final {
 236                                 stream_running = false;
 237                             }
 238                             let subs: Vec<_> =
 239                                 adapters.read().unwrap().stream.values().cloned().collect();
 240                             for s in subs {
 241                                 s.stream_data(frame_number, is_final, data.clone());
 242                             }
 243                         }
 244                     }
 245                     _ => (),
 246                 }
 247             }
 248         }
 249     });
 250 }
 251
 252 fn spawn_writer<T: Tnc>(mut tnc: T, event_rx: mpsc::Receiver<TncControlEvent>) {
 253     std::thread::spawn(move || {
 254         while let Ok(ev) = event_rx.recv() {
 255             match ev {
 256                 TncControlEvent::Kiss(k) => {
 257                     if let Err(e) = tnc.write_all(&k.as_bytes()) {
 258                         debug!("kiss send err: {:?}", e);
 259                         return;
 260                     }
 261                 }
 262                 TncControlEvent::Start => {
 263                     if let Err(e) = tnc.start() {
 264                         debug!("tnc start err: {:?}", e);
 265                         return;
 266                     }
 267                 }
 268                 TncControlEvent::Close => {
 269                     if let Err(e) = tnc.close() {
 270                         debug!("tnc close err: {:?}", e);
 271                         return;
 272                     }
 273                 }
 274             }
 275         }
 276     });
 277 }