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     pub fn transmit_packet(&self, packet_type: PacketType, payload: &[u8]) {
  64         // hang on where do we get the LSF details from? We need a destination obviously
  65         // our source address needs to be configured here too
  66         // also there is possible CAN, encryption, meta payload
  67
  68         // we will immediately convert this into a KISS payload before sending into channel so we only need borrow on data
  69     }
  70
  71     /// Create a handle that can be used to transmit data on the TNC
  72     pub fn tx(&self) -> TxHandle {
  73         TxHandle {
  74             event_tx: self.event_tx.clone(),
  75         }
  76     }
  77
  78     pub fn start(&self) {
  79         let _ = self.event_tx.send(TncControlEvent::Start);
  80     }
  81
  82     pub fn close(&self) {
  83         let _ = self.event_tx.send(TncControlEvent::Close);
  84     }
  85 }
  86
  87 pub struct TxHandle {
  88     event_tx: mpsc::SyncSender<TncControlEvent>,
  89 }
  90
  91 impl TxHandle {
  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 + Send + 'static>(mut tnc: T, listeners: Arc<RwLock<Adapters>>) {
 129     std::thread::spawn(move || {
 130         let mut kiss_buffer = KissBuffer::new();
 131         loop {
 132             let mut buf = kiss_buffer.buf_remaining();
 133             let n = match tnc.read(&mut buf) {
 134                 Ok(n) => n,
 135                 Err(_) => break,
 136             };
 137             kiss_buffer.did_write(n);
 138             while let Some(frame) = kiss_buffer.next_frame() {
 139                 if frame.command() != Ok(KissCommand::DataFrame) {
 140                     continue;
 141                 }
 142                 match frame.port() {
 143                     Ok(m17core::kiss::PORT_PACKET_BASIC) => {
 144                         // no action
 145                         // we will handle the more full-featured version from from port 1
 146                     }
 147                     Ok(m17core::kiss::PORT_PACKET_FULL) => {
 148                         let mut payload = [0u8; 855]; // 30 byte LSF + 825 byte packet including CRC
 149                         let Ok(n) = frame.decode_payload(&mut payload) else {
 150                             debug!("failed to decode payload from KISS frame");
 151                             continue;
 152                         };
 153                         if n < 33 {
 154                             debug!("unusually short full packet frame");
 155                             continue;
 156                         }
 157                         let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 158                         if lsf.crc() != 0 {
 159                             debug!("LSF in full packet frame did not pass CRC");
 160                             continue;
 161                         }
 162                         if lsf.encryption_type() != EncryptionType::None {
 163                             debug!("we only understand None encryption for now - skipping packet");
 164                             continue;
 165                         }
 166                         let Some((packet_type, type_len)) = PacketType::from_proto(&payload[30..n])
 167                         else {
 168                             debug!("failed to decode packet type");
 169                             continue;
 170                         };
 171                         if (n - 30 - type_len) < 2 {
 172                             debug!("packet payload too small to provide CRC");
 173                             continue;
 174                         }
 175                         let packet_crc = m17core::crc::m17_crc(&payload[30..n]);
 176                         if packet_crc != 0 {
 177                             debug!("packet CRC does not pass");
 178                             continue;
 179                         }
 180                         let packet_payload: Arc<[u8]> =
 181                             Arc::from(&payload[(30 + type_len)..(n - 2)]);
 182
 183                         let subs: Vec<_> =
 184                             listeners.read().unwrap().packet.values().cloned().collect();
 185                         for s in subs {
 186                             s.packet_received(
 187                                 lsf.clone(),
 188                                 packet_type.clone(),
 189                                 packet_payload.clone(),
 190                             );
 191                         }
 192                     }
 193                     Ok(m17core::kiss::PORT_STREAM) => {
 194                         // handle stream and send it to subscribers
 195                     }
 196                     _ => (),
 197                 }
 198             }
 199         }
 200     });
 201 }
 202
 203 fn spawn_writer<T: Tnc + Send + 'static>(mut tnc: T, event_rx: mpsc::Receiver<TncControlEvent>) {
 204     std::thread::spawn(move || {
 205         while let Ok(ev) = event_rx.recv() {
 206             match ev {
 207                 TncControlEvent::Kiss(k) => {
 208                     if let Err(e) = tnc.write_all(&k.as_bytes()) {
 209                         debug!("kiss send err: {:?}", e);
 210                         return;
 211                     }
 212                 }
 213                 TncControlEvent::Start => {
 214                     if let Err(e) = tnc.start() {
 215                         debug!("tnc start err: {:?}", e);
 216                         return;
 217                     }
 218                 }
 219                 TncControlEvent::Close => {
 220                     if let Err(e) = tnc.close() {
 221                         debug!("tnc close err: {:?}", e);
 222                         return;
 223                     }
 224                 }
 225             }
 226         }
 227     });
 228 }