From: Lizzy Fleckenstein <eliasfleckenstein@web.de>
Date: Sun, 26 Feb 2023 02:02:06 +0000 (+0100)
Subject: Implement sending splits
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=a4c3c05c69a4f9de76e41980594d180ec9ffe03b;p=mt_rudp.git

Implement sending splits
---

diff --git a/README.md b/README.md
index d40c495..6c78232 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,6 @@ This library is the first piece in a ecosystem of Rust libraries for building se
 
 ## TODO
 
-- implement sending split packets
 - implement server
 - implement reliable window
 - documentation
diff --git a/src/common.rs b/src/common.rs
index bdae6d2..9d99cb9 100644
--- a/src/common.rs
+++ b/src/common.rs
@@ -52,3 +52,17 @@ pub struct Pkt<'a> {
     pub chan: u8,
     pub data: Cow<'a, [u8]>,
 }
+
+impl<'a> Pkt<'a> {
+    pub fn size(&self) -> usize {
+        self.header_size() + self.body_size()
+    }
+
+    pub fn body_size(&self) -> usize {
+        self.data.len()
+    }
+
+    pub fn header_size(&self) -> usize {
+        4 + 2 + 1 + if self.unrel { 0 } else { 1 + 2 } + 1
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index b9a042d..ddbda5c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,6 @@
 #![feature(cursor_remaining)]
 #![feature(hash_drain_filter)]
+#![feature(int_roundings)]
 
 mod client;
 mod common;
diff --git a/src/send.rs b/src/send.rs
index 90bbe2d..3681eb9 100644
--- a/src/send.rs
+++ b/src/send.rs
@@ -1,6 +1,7 @@
 use super::*;
 use byteorder::{BigEndian, WriteBytesExt};
 use std::{
+    borrow::Cow,
     collections::HashMap,
     io::{self, Write},
     sync::Arc,
@@ -20,6 +21,7 @@ pub(crate) struct AckWait {
 pub(crate) struct Chan {
     pub(crate) acks: HashMap<u16, AckWait>,
     pub(crate) seqnum: u16,
+    pub(crate) splits_seqnum: u16,
 }
 
 #[derive(Debug)]
@@ -42,17 +44,58 @@ impl<S: UdpSender> Sender<S> {
                 Mutex::new(Chan {
                     acks: HashMap::new(),
                     seqnum: INIT_SEQNUM,
+                    splits_seqnum: INIT_SEQNUM,
                 })
             }),
         })
     }
 
     pub async fn send_rudp(&self, pkt: Pkt<'_>) -> io::Result<Ack> {
-        self.send_rudp_type(PktType::Orig, pkt).await // TODO: splits
+        if pkt.size() > UDP_PKT_SIZE {
+            let chunks = pkt
+                .data
+                .chunks(UDP_PKT_SIZE - (pkt.header_size() + 1 + 2 + 2 + 2));
+            let num_chunks: u16 = chunks
+                .len()
+                .try_into()
+                .map_err(|_| io::Error::new(io::ErrorKind::Other, "too many chunks"))?;
+
+            let seqnum = {
+                let mut chan = self.chans[pkt.chan as usize].lock().await;
+                let sn = chan.splits_seqnum;
+                chan.splits_seqnum = chan.splits_seqnum.overflowing_add(1).0;
+
+                sn
+            };
+
+            for (i, ch) in chunks.enumerate() {
+                self.send_rudp_type(
+                    PktType::Orig,
+                    Some((seqnum, num_chunks, i as u16)),
+                    Pkt {
+                        unrel: pkt.unrel,
+                        chan: pkt.chan,
+                        data: Cow::Borrowed(ch),
+                    },
+                )
+                .await?;
+            }
+
+            Ok(None) // TODO: ack
+        } else {
+            self.send_rudp_type(PktType::Orig, None, pkt).await
+        }
     }
 
-    pub async fn send_rudp_type(&self, tp: PktType, pkt: Pkt<'_>) -> io::Result<Ack> {
-        let mut buf = Vec::with_capacity(4 + 2 + 1 + 1 + 2 + 1 + pkt.data.len());
+    pub async fn send_rudp_type(
+        &self,
+        tp: PktType,
+        chunk: Option<(u16, u16, u16)>,
+        pkt: Pkt<'_>,
+    ) -> io::Result<Ack> {
+        let mut buf =
+            Vec::with_capacity(pkt.size() + if chunk.is_some() { 1 + 2 + 2 + 2 } else { 0 });
+
         buf.write_u32::<BigEndian>(PROTO_ID)?;
         buf.write_u16::<BigEndian>(*self.remote_id.read().await)?;
         buf.write_u8(pkt.chan)?;
@@ -65,7 +108,15 @@ impl<S: UdpSender> Sender<S> {
             buf.write_u16::<BigEndian>(seqnum)?;
         }
 
-        buf.write_u8(tp as u8)?;
+        if let Some((seqnum, count, index)) = chunk {
+            buf.write_u8(PktType::Split as u8)?;
+            buf.write_u16::<BigEndian>(seqnum)?;
+            buf.write_u16::<BigEndian>(count)?;
+            buf.write_u16::<BigEndian>(index)?;
+        } else {
+            buf.write_u8(tp as u8)?;
+        }
+
         buf.write_all(pkt.data.as_ref())?;
 
         self.send_udp(&buf).await?;
@@ -91,7 +142,10 @@ impl<S: UdpSender> Sender<S> {
 
     pub async fn send_udp(&self, data: &[u8]) -> io::Result<()> {
         if data.len() > UDP_PKT_SIZE {
-            panic!("splitting packets is not implemented yet");
+            panic!(
+                "attempted to send a packet with len {} > {UDP_PKT_SIZE}",
+                data.len()
+            );
         }
 
         self.udp.send(data).await
diff --git a/src/worker.rs b/src/worker.rs
index 8210e63..daec64e 100644
--- a/src/worker.rs
+++ b/src/worker.rs
@@ -82,6 +82,7 @@ impl<S: UdpSender, R: UdpReceiver> Worker<S, R> {
                     self.sender
                         .send_rudp_type(
                             PktType::Ctl,
+                            None,
                             Pkt {
                                 unrel: true,
                                 chan: 0,
@@ -121,6 +122,7 @@ impl<S: UdpSender, R: UdpReceiver> Worker<S, R> {
                     self.sender
                         .send_rudp_type(
                             PktType::Ctl,
+                            None,
                             Pkt {
                                 chan: 0,
                                 unrel: false,
@@ -260,6 +262,8 @@ impl<S: UdpSender, R: UdpReceiver> Worker<S, R> {
                 let seqnum = cursor.read_u16::<BigEndian>()?;
                 self.chans[ch].packets[to_seqnum(seqnum)].replace(cursor.remaining_slice().into());
 
+                println!("{seqnum}");
+
                 let mut ack_data = Vec::with_capacity(3);
                 ack_data.write_u8(CtlType::Ack as u8)?;
                 ack_data.write_u16::<BigEndian>(seqnum)?;
@@ -267,6 +271,7 @@ impl<S: UdpSender, R: UdpReceiver> Worker<S, R> {
                 self.sender
                     .send_rudp_type(
                         PktType::Ctl,
+                        None,
                         Pkt {
                             chan,
                             unrel: true,