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

   1 use crate::adapter::{PacketAdapter, StreamAdapter};
   2 use crate::link_setup::LinkSetup;
   3 use crate::tnc::Tnc;
   4 use m17core::kiss::{KissBuffer, KissCommand, KissFrame};
   5 use m17core::protocol::{EncryptionType, LsfFrame, PacketType, StreamFrame};
   6
   7 use log::debug;
   8 use std::collections::HashMap;
   9 use std::sync::mpsc;
  10 use std::sync::{Arc, RwLock};
  11
  12 pub struct M17App {
  13     adapters: Arc<RwLock<Adapters>>,
  14     event_tx: mpsc::SyncSender<TncControlEvent>,
  15 }
  16
  17 impl M17App {
  18     pub fn new<T: Tnc + Send + 'static>(mut tnc: T) -> Self {
  19         let write_tnc = tnc.try_clone().unwrap();
  20         let (event_tx, event_rx) = mpsc::sync_channel(128);
  21         let listeners = Arc::new(RwLock::new(Adapters::new()));
  22         spawn_reader(tnc, listeners.clone());
  23         spawn_writer(write_tnc, event_rx);
  24         Self {
  25             adapters: listeners,
  26             event_tx,
  27         }
  28     }
  29
  30     pub fn add_packet_adapter<P: PacketAdapter + 'static>(&self, adapter: P) -> usize {
  31         let adapter = Arc::new(adapter);
  32         let mut adapters = self.adapters.write().unwrap();
  33         let id = adapters.next;
  34         adapters.next += 1;
  35         adapters.packet.insert(id, adapter.clone());
  36         drop(adapters);
  37         adapter.adapter_registered(id, self.tx());
  38         id
  39     }
  40
  41     pub fn add_stream_adapter<S: StreamAdapter + 'static>(&self, adapter: S) -> usize {
  42         let adapter = Arc::new(adapter);
  43         let mut adapters = self.adapters.write().unwrap();
  44         let id = adapters.next;
  45         adapters.next += 1;
  46         adapters.stream.insert(id, adapter.clone());
  47         drop(adapters);
  48         adapter.adapter_registered(id, self.tx());
  49         id
  50     }
  51
  52     pub fn remove_packet_adapter(&self, id: usize) {
  53         if let Some(a) = self.adapters.write().unwrap().packet.remove(&id) {
  54             a.adapter_removed();
  55         }
  56     }
  57
  58     pub fn remove_stream_adapter(&self, id: usize) {
  59         if let Some(a) = self.adapters.write().unwrap().stream.remove(&id) {
  60             a.adapter_removed();
  61         }
  62     }
  63
  64     /// Create a handle that can be used to transmit data on the TNC
  65     pub fn tx(&self) -> TxHandle {
  66         TxHandle {
  67             event_tx: self.event_tx.clone(),
  68         }
  69     }
  70
  71     pub fn start(&self) {
  72         let _ = self.event_tx.send(TncControlEvent::Start);
  73     }
  74
  75     pub fn close(&self) {
  76         // TODO: blocking function to indicate TNC has finished closing
  77         // then we could call this in a signal handler to ensure PTT is dropped before quit
  78         let _ = self.event_tx.send(TncControlEvent::Close);
  79     }
  80 }
  81
  82 pub struct TxHandle {
  83     event_tx: mpsc::SyncSender<TncControlEvent>,
  84 }
  85
  86 impl TxHandle {
  87     pub fn transmit_packet(&self, link_setup: &LinkSetup, packet_type: PacketType, payload: &[u8]) {
  88         let (pack_type, pack_type_len) = packet_type.as_proto();
  89         if pack_type_len + payload.len() > 823 {
  90             // TODO: error for invalid transmission type
  91             return;
  92         }
  93         let mut full_payload = vec![];
  94         full_payload.extend_from_slice(&pack_type[0..pack_type_len]);
  95         full_payload.extend_from_slice(&payload);
  96         let crc = m17core::crc::m17_crc(&full_payload);
  97         full_payload.extend_from_slice(&crc.to_be_bytes());
  98         let kiss_frame = KissFrame::new_full_packet(&link_setup.raw.0, &full_payload).unwrap();
  99         let _ = self.event_tx.send(TncControlEvent::Kiss(kiss_frame));
 100     }
 101
 102     pub fn transmit_stream_start(&self, link_setup: &LinkSetup) {
 103         let kiss_frame = KissFrame::new_stream_setup(&link_setup.raw.0).unwrap();
 104         let _ = self.event_tx.send(TncControlEvent::Kiss(kiss_frame));
 105     }
 106
 107     // as long as there is only one TNC it is implied there is only ever one stream transmission in flight
 108
 109     pub fn transmit_stream_next(&self, stream: &StreamFrame) {
 110         let kiss_frame = KissFrame::new_stream_data(&stream).unwrap();
 111         let _ = self.event_tx.send(TncControlEvent::Kiss(kiss_frame));
 112     }
 113 }
 114
 115 /// Synchronised structure for listeners subscribing to packets and streams.
 116 ///
 117 /// Each listener will be notified in turn of each event.
 118 struct Adapters {
 119     /// Identifier to be assigned to the next listener, starting from 0
 120     next: usize,
 121     packet: HashMap<usize, Arc<dyn PacketAdapter>>,
 122     stream: HashMap<usize, Arc<dyn StreamAdapter>>,
 123 }
 124
 125 impl Adapters {
 126     fn new() -> Self {
 127         Self {
 128             next: 0,
 129             packet: HashMap::new(),
 130             stream: HashMap::new(),
 131         }
 132     }
 133 }
 134
 135 /// Carries a request from a method on M17App to the TNC's writer thread, which will execute it.
 136 enum TncControlEvent {
 137     Kiss(KissFrame),
 138     Start,
 139     Close,
 140 }
 141
 142 fn spawn_reader<T: Tnc>(mut tnc: T, adapters: Arc<RwLock<Adapters>>) {
 143     std::thread::spawn(move || {
 144         let mut kiss_buffer = KissBuffer::new();
 145         let mut stream_running = false;
 146         loop {
 147             let mut buf = kiss_buffer.buf_remaining();
 148             let n = match tnc.read(&mut buf) {
 149                 Ok(n) => n,
 150                 Err(_) => break,
 151             };
 152             kiss_buffer.did_write(n);
 153             while let Some(frame) = kiss_buffer.next_frame() {
 154                 if frame.command() != Ok(KissCommand::DataFrame) {
 155                     continue;
 156                 }
 157                 match frame.port() {
 158                     Ok(m17core::kiss::PORT_PACKET_BASIC) => {
 159                         // no action
 160                         // we will handle the more full-featured version from from port 1
 161                     }
 162                     Ok(m17core::kiss::PORT_PACKET_FULL) => {
 163                         let mut payload = [0u8; 855]; // 30 byte LSF + 825 byte packet including CRC
 164                         let Ok(n) = frame.decode_payload(&mut payload) else {
 165                             debug!("failed to decode payload from KISS frame");
 166                             continue;
 167                         };
 168                         if n < 33 {
 169                             debug!("unusually short full packet frame");
 170                             continue;
 171                         }
 172                         let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 173                         if lsf.check_crc() != 0 {
 174                             debug!("LSF in full packet frame did not pass CRC");
 175                             continue;
 176                         }
 177                         if lsf.encryption_type() != EncryptionType::None {
 178                             debug!("we only understand None encryption for now - skipping packet");
 179                             continue;
 180                         }
 181                         let Some((packet_type, type_len)) = PacketType::from_proto(&payload[30..n])
 182                         else {
 183                             debug!("failed to decode packet type");
 184                             continue;
 185                         };
 186                         if (n - 30 - type_len) < 2 {
 187                             debug!("packet payload too small to provide CRC");
 188                             continue;
 189                         }
 190                         let packet_crc = m17core::crc::m17_crc(&payload[30..n]);
 191                         if packet_crc != 0 {
 192                             debug!("packet CRC does not pass");
 193                             continue;
 194                         }
 195                         let packet_payload: Arc<[u8]> =
 196                             Arc::from(&payload[(30 + type_len)..(n - 2)]);
 197
 198                         let subs: Vec<_> =
 199                             adapters.read().unwrap().packet.values().cloned().collect();
 200                         for s in subs {
 201                             s.packet_received(
 202                                 LinkSetup::new_raw(lsf.clone()),
 203                                 packet_type.clone(),
 204                                 packet_payload.clone(),
 205                             );
 206                         }
 207                     }
 208                     Ok(m17core::kiss::PORT_STREAM) => {
 209                         let mut payload = [0u8; 32];
 210                         let Ok(n) = frame.decode_payload(&mut payload) else {
 211                             debug!("failed to decode stream payload from KISS frame");
 212                             continue;
 213                         };
 214                         if n == 30 {
 215                             let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 216                             if lsf.check_crc() != 0 {
 217                                 debug!("initial LSF in stream did not pass CRC");
 218                                 continue;
 219                             }
 220                             stream_running = true;
 221                             let subs: Vec<_> =
 222                                 adapters.read().unwrap().stream.values().cloned().collect();
 223                             for s in subs {
 224                                 s.stream_began(LinkSetup::new_raw(lsf.clone()));
 225                             }
 226                         } else if n == 26 {
 227                             if !stream_running {
 228                                 debug!("ignoring stream data as we didn't get a valid LSF first");
 229                                 continue;
 230                             }
 231                             // TODO: parse LICH and handle the different changing subvalues META could have
 232                             if m17core::crc::m17_crc(&payload[6..n]) != 0 {
 233                                 debug!("stream data CRC mismatch");
 234                                 continue;
 235                             }
 236                             let mut frame_number = u16::from_be_bytes([payload[6], payload[7]]);
 237                             let is_final = (frame_number & 0x8000) > 0;
 238                             frame_number &= 0x7fff;
 239                             let data: [u8; 16] = payload[8..24].try_into().unwrap();
 240                             let data = Arc::new(data);
 241                             if is_final {
 242                                 stream_running = false;
 243                             }
 244                             let subs: Vec<_> =
 245                                 adapters.read().unwrap().stream.values().cloned().collect();
 246                             for s in subs {
 247                                 s.stream_data(frame_number, is_final, data.clone());
 248                             }
 249                         }
 250                     }
 251                     _ => (),
 252                 }
 253             }
 254         }
 255     });
 256 }
 257
 258 fn spawn_writer<T: Tnc>(mut tnc: T, event_rx: mpsc::Receiver<TncControlEvent>) {
 259     std::thread::spawn(move || {
 260         while let Ok(ev) = event_rx.recv() {
 261             match ev {
 262                 TncControlEvent::Kiss(k) => {
 263                     if let Err(e) = tnc.write_all(&k.as_bytes()) {
 264                         debug!("kiss send err: {:?}", e);
 265                         return;
 266                     }
 267                 }
 268                 TncControlEvent::Start => {
 269                     if let Err(e) = tnc.start() {
 270                         debug!("tnc start err: {:?}", e);
 271                         return;
 272                     }
 273                 }
 274                 TncControlEvent::Close => {
 275                     if let Err(e) = tnc.close() {
 276                         debug!("tnc close err: {:?}", e);
 277                         return;
 278                     }
 279                 }
 280             }
 281         }
 282     });
 283 }