1 files changed, 136 insertions, 0 deletions
diff --git a/src/recv_worker.rs b/src/recv_worker.rs
new file mode 100644
index 0000000..d1ae5b1
--- /dev/null
+++ b/src/recv_worker.rs
@@ -0,0 +1,136 @@
+use crate::{error::Error, CtlType, InPkt, Pkt, PktType, RudpShare, UdpReceiver, UdpSender};
+use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
+use num_enum::{TryFromPrimitive, TryFromPrimitiveError};
+use std::{
+    cell::Cell,
+    io, result,
+    sync::{mpsc, Arc},
+};
+
+fn to_seqnum(seqnum: u16) -> usize {
+    (seqnum as usize) & (crate::REL_BUFFER - 1)
+}
+
+struct RelChan {
+    packets: Vec<Cell<Option<Vec<u8>>>>, // in the good old days this used to be called char **
+    seqnum: u16,
+    num: u8,
+}
+
+type PktTx = mpsc::Sender<InPkt>;
+type Result = result::Result<(), Error>;
+
+pub struct RecvWorker<R: UdpReceiver, S: UdpSender> {
+    share: Arc<RudpShare<S>>,
+    pkt_tx: PktTx,
+    udp_rx: R,
+}
+
+impl<R: UdpReceiver, S: UdpSender> RecvWorker<R, S> {
+    pub fn new(udp_rx: R, share: Arc<RudpShare<S>>, pkt_tx: PktTx) -> Self {
+        Self {
+            udp_rx,
+            share,
+            pkt_tx,
+        }
+    }
+
+    pub fn run(&self) {
+        let mut recv_chans = (0..crate::NUM_CHANS as u8)
+            .map(|num| RelChan {
+                num,
+                packets: (0..crate::REL_BUFFER).map(|_| Cell::new(None)).collect(),
+                seqnum: crate::INIT_SEQNUM,
+            })
+            .collect();
+
+        loop {
+            if let Err(e) = self.handle(self.recv_pkt(&mut recv_chans)) {
+                if let Error::LocalDisco = e {
+                    self.share
+                        .send(
+                            PktType::Ctl,
+                            Pkt {
+                                unrel: true,
+                                chan: 0,
+                                data: &[CtlType::Disco as u8],
+                            },
+                        )
+                        .ok();
+                }
+                break;
+            }
+        }
+    }
+
+    fn recv_pkt(&self, chans: &mut Vec<RelChan>) -> Result {
+        use Error::*;
+
+        // todo: reset timeout
+        let mut cursor = io::Cursor::new(self.udp_rx.recv()?);
+
+        let proto_id = cursor.read_u32::<BigEndian>()?;
+        if proto_id != crate::PROTO_ID {
+            do yeet InvalidProtoId(proto_id);
+        }
+
+        let peer_id = cursor.read_u16::<BigEndian>()?;
+
+        let n_chan = cursor.read_u8()?;
+        let chan = chans
+            .get_mut(n_chan as usize)
+            .ok_or(InvalidChannel(n_chan))?;
+
+        self.process_pkt(cursor, chan)
+    }
+
+    fn process_pkt(&self, mut cursor: io::Cursor<Vec<u8>>, chan: &mut RelChan) -> Result {
+        use CtlType::*;
+        use Error::*;
+        use PktType::*;
+
+        match cursor.read_u8()?.try_into()? {
+            Ctl => match cursor.read_u8()?.try_into()? {
+                Disco => return Err(RemoteDisco),
+                _ => {}
+            },
+            Orig => {
+                println!("Orig");
+
+                self.pkt_tx.send(Ok(Pkt {
+                    chan: chan.num,
+                    unrel: true,
+                    data: cursor.remaining_slice().into(),
+                }))?;
+            }
+            Split => {
+                println!("Split");
+                dbg!(cursor.remaining_slice());
+            }
+            Rel => {
+                println!("Rel");
+
+                let seqnum = cursor.read_u16::<BigEndian>()?;
+                chan.packets[to_seqnum(seqnum)].set(Some(cursor.remaining_slice().into()));
+
+                while let Some(pkt) = chan.packets[to_seqnum(chan.seqnum)].take() {
+                    self.handle(self.process_pkt(io::Cursor::new(pkt), chan))?;
+                    chan.seqnum = chan.seqnum.overflowing_add(1).0;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn handle(&self, res: Result) -> Result {
+        use Error::*;
+
+        match res {
+            Ok(v) => Ok(v),
+            Err(RemoteDisco) => Err(RemoteDisco),
+            Err(LocalDisco) => Err(LocalDisco),
+            Err(e) => Ok(self.pkt_tx.send(Err(e))?),
+        }
+    }
+}