Add config API for copa algorithm (#382)

include/tquic.h

@@ -597,6 +597,21 @@ void quic_config_set_bbr_rtprop_filter_len(struct quic_config_t *config, uint64_
  */
 void quic_config_set_bbr_probe_bw_cwnd_gain(struct quic_config_t *config, double v);
 
+/**
+ * Set the delta in copa slow start state.
+ */
+void quic_config_set_copa_slow_start_delta(struct quic_config_t *config, double v);
+
+/**
+ * Set the delta in coap steady state.
+ */
+void quic_config_set_copa_steady_delta(struct quic_config_t *config, double v);
+
+/**
+ * Enable Using the rtt standing instead of the latest rtt to calculate queueing delay.
+ */
+void quic_config_enable_copa_use_standing_rtt(struct quic_config_t *config, bool v);
+
 /**
  * Set the initial RTT in milliseconds. The default value is 333ms.
  * The configuration should be changed with caution. Setting a value less than the default

src/congestion_control/congestion_control.rs

@@ -30,6 +30,7 @@ pub use bbr3::Bbr3;
 pub use bbr3::Bbr3Config;
 pub use copa::Copa;
 pub use copa::CopaConfig;
+pub use copa::COPA_DELTA;
 pub use cubic::Cubic;
 pub use cubic::CubicConfig;
 pub use dummy::Dummy;

src/congestion_control/copa.rs

@@ -36,7 +36,7 @@ use crate::connection::space::SentPacket;
 use crate::RecoveryConfig;
 
 /// Delta: determines how much to weigh delay compared to throughput.
-const COPA_DELTA: f64 = 0.04;
+pub const COPA_DELTA: f64 = 0.04;
 
 /// Max count while cwnd grows with the same direction. Speed up if
 /// the count exceeds threshold.
@@ -100,9 +100,9 @@ impl CopaConfig {
             initial_cwnd,
             initial_rtt,
             max_datagram_size,
-            slow_start_delta: COPA_DELTA,
-            steady_delta: COPA_DELTA,
-            use_standing_rtt: true,
+            slow_start_delta: conf.copa_slow_start_delta,
+            steady_delta: conf.copa_steady_delta,
+            use_standing_rtt: conf.copa_use_standing_rtt,
         }
     }
 }

src/ffi.rs

@@ -342,6 +342,24 @@ pub extern "C" fn quic_config_set_bbr_probe_bw_cwnd_gain(config: &mut Config, v:
     config.set_bbr_probe_bw_cwnd_gain(v);
 }
 
+/// Set the delta in copa slow start state.
+#[no_mangle]
+pub extern "C" fn quic_config_set_copa_slow_start_delta(config: &mut Config, v: f64) {
+    config.set_copa_slow_start_delta(v);
+}
+
+/// Set the delta in coap steady state.
+#[no_mangle]
+pub extern "C" fn quic_config_set_copa_steady_delta(config: &mut Config, v: f64) {
+    config.set_copa_steady_delta(v);
+}
+
+/// Enable Using the rtt standing instead of the latest rtt to calculate queueing delay.
+#[no_mangle]
+pub extern "C" fn quic_config_enable_copa_use_standing_rtt(config: &mut Config, v: bool) {
+    config.enable_copa_use_standing_rtt(v);
+}
+
 /// Set the initial RTT in milliseconds. The default value is 333ms.
 /// The configuration should be changed with caution. Setting a value less than the default
 /// will cause retransmission of handshake packets to be more aggressive.

src/lib.rs

@@ -551,6 +551,21 @@ impl Config {
         self.recovery.bbr_probe_bw_cwnd_gain = v;
     }
 
+    /// Set the delta in copa slow start state.
+    pub fn set_copa_slow_start_delta(&mut self, v: f64) {
+        self.recovery.copa_slow_start_delta = v;
+    }
+
+    /// Set the delta in coap steady state.
+    pub fn set_copa_steady_delta(&mut self, v: f64) {
+        self.recovery.copa_steady_delta = v;
+    }
+
+    /// Enable Using the rtt standing instead of the latest rtt to calculate queueing delay.
+    pub fn enable_copa_use_standing_rtt(&mut self, v: bool) {
+        self.recovery.copa_use_standing_rtt = v;
+    }
+
     /// Set the initial RTT in milliseconds. The default value is 333ms.
     ///
     /// The configuration should be changed with caution. Setting a value less than the default
@@ -796,6 +811,15 @@ pub struct RecoveryConfig {
     /// The cwnd gain for ProbeBW state
     pub bbr_probe_bw_cwnd_gain: f64,
 
+    /// Delta in copa slow start state.
+    pub copa_slow_start_delta: f64,
+
+    /// Delta in coap steady state.
+    pub copa_steady_delta: f64,
+
+    /// Use rtt standing instead of latest rtt to calculate queueing delay
+    pub copa_use_standing_rtt: bool,
+
     /// The initial rtt, used before real rtt is estimated.
     pub initial_rtt: Duration,
 
@@ -827,6 +851,9 @@ impl Default for RecoveryConfig {
             bbr_probe_rtt_cwnd_gain: 0.75,
             bbr_rtprop_filter_len: Duration::from_secs(10),
             bbr_probe_bw_cwnd_gain: 2.0,
+            copa_slow_start_delta: congestion_control::COPA_DELTA,
+            copa_steady_delta: congestion_control::COPA_DELTA,
+            copa_use_standing_rtt: true,
             initial_rtt: INITIAL_RTT,
             enable_pacing: true,
             pacing_granularity: time::Duration::from_millis(1),