1 files changed, 130 insertions, 0 deletions
diff --git a/third_party/rust/neqo-transport/src/sender.rs b/third_party/rust/neqo-transport/src/sender.rs
new file mode 100644
index 0000000000..9a00dfc7a7
--- /dev/null
+++ b/third_party/rust/neqo-transport/src/sender.rs
@@ -0,0 +1,130 @@
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// Congestion control
+#![deny(clippy::pedantic)]
+#![allow(clippy::module_name_repetitions)]
+
+use std::{
+    fmt::{self, Debug, Display},
+    time::{Duration, Instant},
+};
+
+use neqo_common::qlog::NeqoQlog;
+
+use crate::{
+    cc::{ClassicCongestionControl, CongestionControl, CongestionControlAlgorithm, Cubic, NewReno},
+    pace::Pacer,
+    rtt::RttEstimate,
+    tracking::SentPacket,
+};
+
+/// The number of packets we allow to burst from the pacer.
+pub const PACING_BURST_SIZE: usize = 2;
+
+#[derive(Debug)]
+pub struct PacketSender {
+    cc: Box<dyn CongestionControl>,
+    pacer: Pacer,
+}
+
+impl Display for PacketSender {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{} {}", self.cc, self.pacer)
+    }
+}
+
+impl PacketSender {
+    #[must_use]
+    pub fn new(
+        alg: CongestionControlAlgorithm,
+        pacing_enabled: bool,
+        mtu: usize,
+        now: Instant,
+    ) -> Self {
+        Self {
+            cc: match alg {
+                CongestionControlAlgorithm::NewReno => {
+                    Box::new(ClassicCongestionControl::new(NewReno::default()))
+                }
+                CongestionControlAlgorithm::Cubic => {
+                    Box::new(ClassicCongestionControl::new(Cubic::default()))
+                }
+            },
+            pacer: Pacer::new(pacing_enabled, now, mtu * PACING_BURST_SIZE, mtu),
+        }
+    }
+
+    pub fn set_qlog(&mut self, qlog: NeqoQlog) {
+        self.cc.set_qlog(qlog);
+    }
+
+    #[must_use]
+    pub fn cwnd(&self) -> usize {
+        self.cc.cwnd()
+    }
+
+    #[must_use]
+    pub fn cwnd_avail(&self) -> usize {
+        self.cc.cwnd_avail()
+    }
+
+    pub fn on_packets_acked(
+        &mut self,
+        acked_pkts: &[SentPacket],
+        rtt_est: &RttEstimate,
+        now: Instant,
+    ) {
+        self.cc.on_packets_acked(acked_pkts, rtt_est, now);
+    }
+
+    /// Called when packets are lost.  Returns true if the congestion window was reduced.
+    pub fn on_packets_lost(
+        &mut self,
+        first_rtt_sample_time: Option<Instant>,
+        prev_largest_acked_sent: Option<Instant>,
+        pto: Duration,
+        lost_packets: &[SentPacket],
+    ) -> bool {
+        self.cc.on_packets_lost(
+            first_rtt_sample_time,
+            prev_largest_acked_sent,
+            pto,
+            lost_packets,
+        )
+    }
+
+    pub fn discard(&mut self, pkt: &SentPacket) {
+        self.cc.discard(pkt);
+    }
+
+    /// When we migrate, the congestion controller for the previously active path drops
+    /// all bytes in flight.
+    pub fn discard_in_flight(&mut self) {
+        self.cc.discard_in_flight();
+    }
+
+    pub fn on_packet_sent(&mut self, pkt: &SentPacket, rtt: Duration) {
+        self.pacer
+            .spend(pkt.time_sent, rtt, self.cc.cwnd(), pkt.size);
+        self.cc.on_packet_sent(pkt);
+    }
+
+    #[must_use]
+    pub fn next_paced(&self, rtt: Duration) -> Option<Instant> {
+        // Only pace if there are bytes in flight.
+        if self.cc.bytes_in_flight() > 0 {
+            Some(self.pacer.next(rtt, self.cc.cwnd()))
+        } else {
+            None
+        }
+    }
+
+    #[must_use]
+    pub fn recovery_packet(&self) -> bool {
+        self.cc.recovery_packet()
+    }
+}