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};
   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?, payload? what needs to be configured ?! */) {}
  95
  96     // as long as there is only one TNC it is implied there is only ever one stream transmission in flight
  97
  98     pub fn transmit_stream_next(&self, /* next payload,  */ end_of_stream: bool) {}
  99 }
 100
 101 /// Synchronised structure for listeners subscribing to packets and streams.
 102 ///
 103 /// Each listener will be notified in turn of each event.
 104 struct Adapters {
 105     /// Identifier to be assigned to the next listener, starting from 0
 106     next: usize,
 107     packet: HashMap<usize, Arc<dyn PacketAdapter>>,
 108     stream: HashMap<usize, Arc<dyn StreamAdapter>>,
 109 }
 110
 111 impl Adapters {
 112     fn new() -> Self {
 113         Self {
 114             next: 0,
 115             packet: HashMap::new(),
 116             stream: HashMap::new(),
 117         }
 118     }
 119 }
 120
 121 /// Carries a request from a method on M17App to the TNC's writer thread, which will execute it.
 122 enum TncControlEvent {
 123     Kiss(KissFrame),
 124     Start,
 125     Close,
 126 }
 127
 128 fn spawn_reader<T: Tnc>(mut tnc: T, adapters: Arc<RwLock<Adapters>>) {
 129     std::thread::spawn(move || {
 130         let mut kiss_buffer = KissBuffer::new();
 131         let mut stream_running = false;
 132         loop {
 133             let mut buf = kiss_buffer.buf_remaining();
 134             let n = match tnc.read(&mut buf) {
 135                 Ok(n) => n,
 136                 Err(_) => break,
 137             };
 138             kiss_buffer.did_write(n);
 139             while let Some(frame) = kiss_buffer.next_frame() {
 140                 if frame.command() != Ok(KissCommand::DataFrame) {
 141                     continue;
 142                 }
 143                 match frame.port() {
 144                     Ok(m17core::kiss::PORT_PACKET_BASIC) => {
 145                         // no action
 146                         // we will handle the more full-featured version from from port 1
 147                     }
 148                     Ok(m17core::kiss::PORT_PACKET_FULL) => {
 149                         let mut payload = [0u8; 855]; // 30 byte LSF + 825 byte packet including CRC
 150                         let Ok(n) = frame.decode_payload(&mut payload) else {
 151                             debug!("failed to decode payload from KISS frame");
 152                             continue;
 153                         };
 154                         if n < 33 {
 155                             debug!("unusually short full packet frame");
 156                             continue;
 157                         }
 158                         let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 159                         if lsf.crc() != 0 {
 160                             debug!("LSF in full packet frame did not pass CRC");
 161                             continue;
 162                         }
 163                         if lsf.encryption_type() != EncryptionType::None {
 164                             debug!("we only understand None encryption for now - skipping packet");
 165                             continue;
 166                         }
 167                         let Some((packet_type, type_len)) = PacketType::from_proto(&payload[30..n])
 168                         else {
 169                             debug!("failed to decode packet type");
 170                             continue;
 171                         };
 172                         if (n - 30 - type_len) < 2 {
 173                             debug!("packet payload too small to provide CRC");
 174                             continue;
 175                         }
 176                         let packet_crc = m17core::crc::m17_crc(&payload[30..n]);
 177                         if packet_crc != 0 {
 178                             debug!("packet CRC does not pass");
 179                             continue;
 180                         }
 181                         let packet_payload: Arc<[u8]> =
 182                             Arc::from(&payload[(30 + type_len)..(n - 2)]);
 183
 184                         let subs: Vec<_> =
 185                             adapters.read().unwrap().packet.values().cloned().collect();
 186                         for s in subs {
 187                             s.packet_received(
 188                                 lsf.clone(),
 189                                 packet_type.clone(),
 190                                 packet_payload.clone(),
 191                             );
 192                         }
 193                     }
 194                     Ok(m17core::kiss::PORT_STREAM) => {
 195                         let mut payload = [0u8; 32];
 196                         let Ok(n) = frame.decode_payload(&mut payload) else {
 197                             debug!("failed to decode stream payload from KISS frame");
 198                             continue;
 199                         };
 200                         if n == 30 {
 201                             let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 202                             if lsf.crc() != 0 {
 203                                 debug!("initial LSF in stream did not pass CRC");
 204                                 continue;
 205                             }
 206                             stream_running = true;
 207                             let subs: Vec<_> =
 208                                 adapters.read().unwrap().stream.values().cloned().collect();
 209                             for s in subs {
 210                                 s.stream_began(lsf.clone());
 211                             }
 212                         } else if n == 26 {
 213                             if !stream_running {
 214                                 debug!("ignoring stream data as we didn't get a valid LSF first");
 215                                 continue;
 216                             }
 217                             // TODO: parse LICH and handle the different changing subvalues META could have
 218                             if m17core::crc::m17_crc(&payload[6..n]) != 0 {
 219                                 debug!("stream data CRC mismatch");
 220                                 continue;
 221                             }
 222                             let mut frame_number = u16::from_be_bytes([payload[6], payload[7]]);
 223                             let is_final = (frame_number & 0x8000) > 0;
 224                             frame_number &= 0x7fff;
 225                             let data: [u8; 16] = payload[8..24].try_into().unwrap();
 226                             let data = Arc::new(data);
 227                             if is_final {
 228                                 stream_running = false;
 229                             }
 230                             let subs: Vec<_> =
 231                                 adapters.read().unwrap().stream.values().cloned().collect();
 232                             for s in subs {
 233                                 s.stream_data(frame_number, is_final, data.clone());
 234                             }
 235                         }
 236                     }
 237                     _ => (),
 238                 }
 239             }
 240         }
 241     });
 242 }
 243
 244 fn spawn_writer<T: Tnc>(mut tnc: T, event_rx: mpsc::Receiver<TncControlEvent>) {
 245     std::thread::spawn(move || {
 246         while let Ok(ev) = event_rx.recv() {
 247             match ev {
 248                 TncControlEvent::Kiss(k) => {
 249                     if let Err(e) = tnc.write_all(&k.as_bytes()) {
 250                         debug!("kiss send err: {:?}", e);
 251                         return;
 252                     }
 253                 }
 254                 TncControlEvent::Start => {
 255                     if let Err(e) = tnc.start() {
 256                         debug!("tnc start err: {:?}", e);
 257                         return;
 258                     }
 259                 }
 260                 TncControlEvent::Close => {
 261                     if let Err(e) = tnc.close() {
 262                         debug!("tnc close err: {:?}", e);
 263                         return;
 264                     }
 265                 }
 266             }
 267         }
 268     });
 269 }