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 #[allow(clippy::large_enum_variant)]
 137 enum TncControlEvent {
 138     Kiss(KissFrame),
 139     Start,
 140     Close,
 141 }
 142
 143 fn spawn_reader<T: Tnc>(mut tnc: T, adapters: Arc<RwLock<Adapters>>) {
 144     std::thread::spawn(move || {
 145         let mut kiss_buffer = KissBuffer::new();
 146         let mut stream_running = false;
 147         loop {
 148             let buf = kiss_buffer.buf_remaining();
 149             let n = match tnc.read(buf) {
 150                 Ok(n) => n,
 151                 Err(_) => break,
 152             };
 153             kiss_buffer.did_write(n);
 154             while let Some(frame) = kiss_buffer.next_frame() {
 155                 if frame.command() != Ok(KissCommand::DataFrame) {
 156                     continue;
 157                 }
 158                 match frame.port() {
 159                     Ok(m17core::kiss::PORT_PACKET_BASIC) => {
 160                         // no action
 161                         // we will handle the more full-featured version from from port 1
 162                     }
 163                     Ok(m17core::kiss::PORT_PACKET_FULL) => {
 164                         let mut payload = [0u8; 855]; // 30 byte LSF + 825 byte packet including CRC
 165                         let Ok(n) = frame.decode_payload(&mut payload) else {
 166                             debug!("failed to decode payload from KISS frame");
 167                             continue;
 168                         };
 169                         if n < 33 {
 170                             debug!("unusually short full packet frame");
 171                             continue;
 172                         }
 173                         let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 174                         if lsf.check_crc() != 0 {
 175                             debug!("LSF in full packet frame did not pass CRC");
 176                             continue;
 177                         }
 178                         if lsf.encryption_type() != EncryptionType::None {
 179                             debug!("we only understand None encryption for now - skipping packet");
 180                             continue;
 181                         }
 182                         let Some((packet_type, type_len)) = PacketType::from_proto(&payload[30..n])
 183                         else {
 184                             debug!("failed to decode packet type");
 185                             continue;
 186                         };
 187                         if (n - 30 - type_len) < 2 {
 188                             debug!("packet payload too small to provide CRC");
 189                             continue;
 190                         }
 191                         let packet_crc = m17core::crc::m17_crc(&payload[30..n]);
 192                         if packet_crc != 0 {
 193                             debug!("packet CRC does not pass");
 194                             continue;
 195                         }
 196                         let packet_payload: Arc<[u8]> =
 197                             Arc::from(&payload[(30 + type_len)..(n - 2)]);
 198
 199                         let subs: Vec<_> =
 200                             adapters.read().unwrap().packet.values().cloned().collect();
 201                         for s in subs {
 202                             s.packet_received(
 203                                 LinkSetup::new_raw(lsf.clone()),
 204                                 packet_type,
 205                                 packet_payload.clone(),
 206                             );
 207                         }
 208                     }
 209                     Ok(m17core::kiss::PORT_STREAM) => {
 210                         let mut payload = [0u8; 32];
 211                         let Ok(n) = frame.decode_payload(&mut payload) else {
 212                             debug!("failed to decode stream payload from KISS frame");
 213                             continue;
 214                         };
 215                         if n == 30 {
 216                             let lsf = LsfFrame(payload[0..30].try_into().unwrap());
 217                             if lsf.check_crc() != 0 {
 218                                 debug!("initial LSF in stream did not pass CRC");
 219                                 continue;
 220                             }
 221                             stream_running = true;
 222                             let subs: Vec<_> =
 223                                 adapters.read().unwrap().stream.values().cloned().collect();
 224                             for s in subs {
 225                                 s.stream_began(LinkSetup::new_raw(lsf.clone()));
 226                             }
 227                         } else if n == 26 {
 228                             if !stream_running {
 229                                 debug!("ignoring stream data as we didn't get a valid LSF first");
 230                                 continue;
 231                             }
 232                             // TODO: parse LICH and handle the different changing subvalues META could have
 233                             if m17core::crc::m17_crc(&payload[6..n]) != 0 {
 234                                 debug!("stream data CRC mismatch");
 235                                 continue;
 236                             }
 237                             let mut frame_number = u16::from_be_bytes([payload[6], payload[7]]);
 238                             let is_final = (frame_number & 0x8000) > 0;
 239                             frame_number &= 0x7fff;
 240                             let data: [u8; 16] = payload[8..24].try_into().unwrap();
 241                             let data = Arc::new(data);
 242                             if is_final {
 243                                 stream_running = false;
 244                             }
 245                             let subs: Vec<_> =
 246                                 adapters.read().unwrap().stream.values().cloned().collect();
 247                             for s in subs {
 248                                 s.stream_data(frame_number, is_final, data.clone());
 249                             }
 250                         }
 251                     }
 252                     _ => (),
 253                 }
 254             }
 255         }
 256     });
 257 }
 258
 259 fn spawn_writer<T: Tnc>(mut tnc: T, event_rx: mpsc::Receiver<TncControlEvent>) {
 260     std::thread::spawn(move || {
 261         while let Ok(ev) = event_rx.recv() {
 262             match ev {
 263                 TncControlEvent::Kiss(k) => {
 264                     if let Err(e) = tnc.write_all(k.as_bytes()) {
 265                         debug!("kiss send err: {:?}", e);
 266                         return;
 267                     }
 268                 }
 269                 TncControlEvent::Start => {
 270                     if let Err(e) = tnc.start() {
 271                         debug!("tnc start err: {:?}", e);
 272                         return;
 273                     }
 274                 }
 275                 TncControlEvent::Close => {
 276                     if let Err(e) = tnc.close() {
 277                         debug!("tnc close err: {:?}", e);
 278                         return;
 279                     }
 280                 }
 281             }
 282         }
 283     });
 284 }