src/recv.rs

   1 use crate::{prelude::*, ticker, RecvChan, RecvWorker, RudpShare, Split};
   2 use async_recursion::async_recursion;
   3 use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
   4 use std::{
   5     cell::OnceCell,
   6     collections::HashMap,
   7     io,
   8     pin::Pin,
   9     sync::Arc,
  10     time::{Duration, Instant},
  11 };
  12 use tokio::sync::{mpsc, watch, Mutex};
  13
  14 fn to_seqnum(seqnum: u16) -> usize {
  15     (seqnum as usize) & (REL_BUFFER - 1)
  16 }
  17
  18 type Result<T> = std::result::Result<T, Error>;
  19
  20 impl<R: UdpReceiver, S: UdpSender> RecvWorker<R, S> {
  21     pub fn new(
  22         udp_rx: R,
  23         share: Arc<RudpShare<S>>,
  24         close: watch::Receiver<bool>,
  25         pkt_tx: mpsc::UnboundedSender<InPkt>,
  26     ) -> Self {
  27         Self {
  28             udp_rx,
  29             share,
  30             close,
  31             pkt_tx,
  32             chans: Arc::new(
  33                 (0..NUM_CHANS as u8)
  34                     .map(|num| {
  35                         Mutex::new(RecvChan {
  36                             num,
  37                             packets: (0..REL_BUFFER).map(|_| None).collect(),
  38                             seqnum: INIT_SEQNUM,
  39                             splits: HashMap::new(),
  40                         })
  41                     })
  42                     .collect(),
  43             ),
  44         }
  45     }
  46
  47     pub async fn run(&self) {
  48         use Error::*;
  49
  50         let cleanup_chans = Arc::clone(&self.chans);
  51         let mut cleanup_close = self.close.clone();
  52         self.share
  53             .tasks
  54             .lock()
  55             .await
  56             /*.build_task()
  57             .name("cleanup_splits")*/
  58             .spawn(async move {
  59                 let timeout = Duration::from_secs(TIMEOUT);
  60
  61                 ticker!(timeout, cleanup_close, {
  62                     for chan_mtx in cleanup_chans.iter() {
  63                         let mut chan = chan_mtx.lock().await;
  64                         chan.splits = chan
  65                             .splits
  66                             .drain_filter(
  67                                 |_k, v| !matches!(v.timestamp, Some(t) if t.elapsed() < timeout),
  68                             )
  69                             .collect();
  70                     }
  71                 });
  72             });
  73
  74         let mut close = self.close.clone();
  75         let timeout = tokio::time::sleep(Duration::from_secs(TIMEOUT));
  76         tokio::pin!(timeout);
  77
  78         loop {
  79             if let Err(e) = self.handle(self.recv_pkt(&mut close, timeout.as_mut()).await) {
  80                 // TODO: figure out whether this is a good idea
  81                 if let RemoteDisco(to) = e {
  82                     self.pkt_tx.send(Err(RemoteDisco(to))).ok();
  83                 }
  84
  85                 #[allow(clippy::single_match)]
  86                 match e {
  87                                         // anon5's mt notifies the peer on timeout, C++ MT does not
  88                                         LocalDisco /*| RemoteDisco(true)*/ => drop(
  89                                                 self.share
  90                                                         .send(
  91                                                                 PktType::Ctl,
  92                                                                 Pkt {
  93                                                                         unrel: true,
  94                                                                         chan: 0,
  95                                                                         data: &[CtlType::Disco as u8],
  96                                                                 },
  97                                                         )
  98                                                         .await
  99                                                         .ok(),
 100                                         ),
 101                                         _ => {}
 102                                 }
 103
 104                 break;
 105             }
 106         }
 107     }
 108
 109     async fn recv_pkt(
 110         &self,
 111         close: &mut watch::Receiver<bool>,
 112         timeout: Pin<&mut tokio::time::Sleep>,
 113     ) -> Result<()> {
 114         use Error::*;
 115
 116         let mut cursor = io::Cursor::new(tokio::select! {
 117             pkt = self.udp_rx.recv() => pkt?,
 118             _ = tokio::time::sleep_until(timeout.deadline()) => return Err(RemoteDisco(true)),
 119             _ = close.changed() => return Err(LocalDisco),
 120         });
 121
 122         timeout.reset(tokio::time::Instant::now() + Duration::from_secs(TIMEOUT));
 123
 124         let proto_id = cursor.read_u32::<BigEndian>()?;
 125         if proto_id != PROTO_ID {
 126             return Err(InvalidProtoId(proto_id));
 127         }
 128
 129         let _peer_id = cursor.read_u16::<BigEndian>()?;
 130
 131         let n_chan = cursor.read_u8()?;
 132         let mut chan = self
 133             .chans
 134             .get(n_chan as usize)
 135             .ok_or(InvalidChannel(n_chan))?
 136             .lock()
 137             .await;
 138
 139         self.process_pkt(cursor, true, &mut chan).await
 140     }
 141
 142     #[async_recursion]
 143     async fn process_pkt(
 144         &self,
 145         mut cursor: io::Cursor<Vec<u8>>,
 146         unrel: bool,
 147         chan: &mut RecvChan,
 148     ) -> Result<()> {
 149         use Error::*;
 150
 151         match cursor.read_u8()?.try_into()? {
 152             PktType::Ctl => match cursor.read_u8()?.try_into()? {
 153                 CtlType::Ack => {
 154                     println!("Ack");
 155
 156                     let seqnum = cursor.read_u16::<BigEndian>()?;
 157                     if let Some(ack) = self.share.chans[chan.num as usize]
 158                         .lock()
 159                         .await
 160                         .acks
 161                         .remove(&seqnum)
 162                     {
 163                         ack.tx.send(true).ok();
 164                     }
 165                 }
 166                 CtlType::SetPeerID => {
 167                     println!("SetPeerID");
 168
 169                     let mut id = self.share.remote_id.write().await;
 170
 171                     if *id != PeerID::Nil as u16 {
 172                         return Err(PeerIDAlreadySet);
 173                     }
 174
 175                     *id = cursor.read_u16::<BigEndian>()?;
 176                 }
 177                 CtlType::Ping => {
 178                     println!("Ping");
 179                 }
 180                 CtlType::Disco => {
 181                     println!("Disco");
 182                     return Err(RemoteDisco(false));
 183                 }
 184             },
 185             PktType::Orig => {
 186                 println!("Orig");
 187
 188                 self.pkt_tx.send(Ok(Pkt {
 189                     chan: chan.num,
 190                     unrel,
 191                     data: cursor.remaining_slice().into(),
 192                 }))?;
 193             }
 194             PktType::Split => {
 195                 println!("Split");
 196
 197                 let seqnum = cursor.read_u16::<BigEndian>()?;
 198                 let chunk_index = cursor.read_u16::<BigEndian>()? as usize;
 199                 let chunk_count = cursor.read_u16::<BigEndian>()? as usize;
 200
 201                 let mut split = chan.splits.entry(seqnum).or_insert_with(|| Split {
 202                     got: 0,
 203                     chunks: (0..chunk_count).map(|_| OnceCell::new()).collect(),
 204                     timestamp: None,
 205                 });
 206
 207                 if split.chunks.len() != chunk_count {
 208                     return Err(InvalidChunkCount(split.chunks.len(), chunk_count));
 209                 }
 210
 211                 if split
 212                     .chunks
 213                     .get(chunk_index)
 214                     .ok_or(InvalidChunkIndex(chunk_index, chunk_count))?
 215                     .set(cursor.remaining_slice().into())
 216                     .is_ok()
 217                 {
 218                     split.got += 1;
 219                 }
 220
 221                 split.timestamp = if unrel { Some(Instant::now()) } else { None };
 222
 223                 if split.got == chunk_count {
 224                     self.pkt_tx.send(Ok(Pkt {
 225                         chan: chan.num,
 226                         unrel,
 227                         data: split
 228                             .chunks
 229                             .iter()
 230                             .flat_map(|chunk| chunk.get().unwrap().iter())
 231                             .copied()
 232                             .collect(),
 233                     }))?;
 234
 235                     chan.splits.remove(&seqnum);
 236                 }
 237             }
 238             PktType::Rel => {
 239                 println!("Rel");
 240
 241                 let seqnum = cursor.read_u16::<BigEndian>()?;
 242                 chan.packets[to_seqnum(seqnum)].replace(cursor.remaining_slice().into());
 243
 244                 let mut ack_data = Vec::with_capacity(3);
 245                 ack_data.write_u8(CtlType::Ack as u8)?;
 246                 ack_data.write_u16::<BigEndian>(seqnum)?;
 247
 248                 self.share
 249                     .send(
 250                         PktType::Ctl,
 251                         Pkt {
 252                             unrel: true,
 253                             chan: chan.num,
 254                             data: &ack_data,
 255                         },
 256                     )
 257                     .await?;
 258
 259                 fn next_pkt(chan: &mut RecvChan) -> Option<Vec<u8>> {
 260                     chan.packets[to_seqnum(chan.seqnum)].take()
 261                 }
 262
 263                 while let Some(pkt) = next_pkt(chan) {
 264                     self.handle(self.process_pkt(io::Cursor::new(pkt), false, chan).await)?;
 265                     chan.seqnum = chan.seqnum.overflowing_add(1).0;
 266                 }
 267             }
 268         }
 269
 270         Ok(())
 271     }
 272
 273     fn handle(&self, res: Result<()>) -> Result<()> {
 274         use Error::*;
 275
 276         match res {
 277             Ok(v) => Ok(v),
 278             Err(RemoteDisco(to)) => Err(RemoteDisco(to)),
 279             Err(LocalDisco) => Err(LocalDisco),
 280             Err(e) => Ok(self.pkt_tx.send(Err(e))?),
 281         }
 282     }
 283 }