feat(platform): introduce abstractions for cross-platform interface statistics and traffic control

Decouple the rate controller from Linux-specific Netlink calls to support other operating systems. This adds a macOS backend for interface statistics and an "observe-only" mode for platforms where traffic shaping is not yet implemented.

Cargo.toml

@@ -21,8 +21,6 @@ strip = "symbols"
 [dependencies]
 anyhow = "1.0"
 icmp-socket2 = "0.4.2"
-netlink-bindings = { git = "https://github.com/one-d-wide/netlink-bindings.git", rev = "0b609e9380610e7da73f8c43cdf804a1d1bf5474", features = ["rt-link", "tc"] }
-netlink-socket2 = { git = "https://github.com/one-d-wide/netlink-bindings.git", rev = "0b609e9380610e7da73f8c43cdf804a1d1bf5474" }
 fastrand = "2"
 rustix = { version = "1.1", features = ["fs", "system", "thread", "time"] }
 thiserror = "2.0"
@@ -34,6 +32,8 @@ features = ["std"]
 version = "0.4"
 
 [target.'cfg(target_os = "linux")'.dependencies]
+netlink-bindings = { git = "https://github.com/one-d-wide/netlink-bindings.git", rev = "0b609e9380610e7da73f8c43cdf804a1d1bf5474", features = ["rt-link", "tc"] }
+netlink-socket2 = { git = "https://github.com/one-d-wide/netlink-bindings.git", rev = "0b609e9380610e7da73f8c43cdf804a1d1bf5474" }
 rust-uci = { git = "https://github.com/namib-project/rust-uci.git", rev = "3e7b6153b6df92b45428c32bb6461756563deecb", optional = true }
 
 [features]

src/log.rs

@@ -3,7 +3,7 @@
 // SPDX-License-Identifier: MPL-2.0
 
 use log::{Level, LevelFilter, Metadata, Record, SetLoggerError};
-use rustix::thread::ClockId;
+use rustix::time::ClockId;
 
 use crate::time::Time;
 

src/main.rs

@@ -11,10 +11,12 @@ mod baseliner;
 mod config;
 mod log;
 mod metrics;
+#[cfg(target_os = "linux")]
 mod netlink;
 mod pinger;
 mod pinger_icmp;
 mod pinger_icmp_ts;
+mod platform;
 mod ratecontroller;
 mod reflector_selector;
 mod time;
@@ -34,10 +36,10 @@ use std::time::{Duration, Instant};
 use std::{process, thread};
 
 use crate::config::{Config, MeasurementType};
-use crate::netlink::{Netlink, Qdisc};
 use crate::pinger::{InFlightProbeCache, PingListener, PingSender};
 use crate::pinger_icmp::{PingerICMPEchoListener, PingerICMPEchoSender};
 use crate::pinger_icmp_ts::{PingerICMPTimestampListener, PingerICMPTimestampSender};
+use crate::platform::{TrafficControlBackend, traffic_control_backend};
 use crate::ratecontroller::{Ratecontroller, StatsDirection};
 use crate::reflector_selector::ReflectorSelector;
 
@@ -101,19 +103,28 @@ fn create_pinger(measurement_type: MeasurementType) -> (PingListenerBox, PingSen
     }
 }
 
-fn initialize_shaper(config: &Config) -> anyhow::Result<(Qdisc, Qdisc)> {
-    let down = Netlink::qdisc_from_ifname(&config.download_interface)?;
-    let up = Netlink::qdisc_from_ifname(&config.upload_interface)?;
+fn initialize_shaper<T: TrafficControlBackend>(
+    config: &Config,
+    traffic_control: &mut T,
+) -> anyhow::Result<(T::Handle, T::Handle)> {
+    initialize_shaper_with_settle_time(config, traffic_control, Duration::from_secs(2))
+}
+
+fn initialize_shaper_with_settle_time<T: TrafficControlBackend>(
+    config: &Config,
+    traffic_control: &mut T,
+    settle_time: Duration,
+) -> anyhow::Result<(T::Handle, T::Handle)> {
+    let down = traffic_control.find_shaper(&config.download_interface)?;
+    let up = traffic_control.find_shaper(&config.upload_interface)?;
 
     info!(
-        "Setting shaper rates to minimum (D/L): {} / {}",
+        "Requesting minimum shaper rates (D/U): {} / {}",
         config.download_min_kbits, config.upload_min_kbits,
     );
 
-    Netlink::set_qdisc_rate(down, config.download_min_kbits as u64, config.dry_run)?;
-    Netlink::set_qdisc_rate(up, config.upload_min_kbits as u64, config.dry_run)?;
-
-    let settle_time = Duration::from_secs(2);
+    traffic_control.set_rate(&down, config.download_min_kbits as u64, config.dry_run)?;
+    traffic_control.set_rate(&up, config.upload_min_kbits as u64, config.dry_run)?;
 
     info!(
         "Sleeping for {} seconds to give the shaper a chance to control existing bloat",
@@ -163,19 +174,25 @@ fn probe_identifier() -> u16 {
     (process::id() & 0xffff) as u16
 }
 
-fn restore_shaper(config: &Config, down: Qdisc, up: Qdisc) {
+fn restore_shaper<T: TrafficControlBackend>(
+    config: &Config,
+    traffic_control: &mut T,
+    down: &T::Handle,
+    up: &T::Handle,
+) {
     info!(
-        "Restoring base shaper rates (D/L): {} / {}",
+        "Requesting restoration to base shaper rates (D/U): {} / {}",
         config.download_base_kbits, config.upload_base_kbits,
     );
 
     if let Err(error) =
-        Netlink::set_qdisc_rate(down, config.download_base_kbits as u64, config.dry_run)
+        traffic_control.set_rate(down, config.download_base_kbits as u64, config.dry_run)
     {
         warn!("Failed to restore download shaper rate: {error}");
     }
 
-    if let Err(error) = Netlink::set_qdisc_rate(up, config.upload_base_kbits as u64, config.dry_run)
+    if let Err(error) =
+        traffic_control.set_rate(up, config.upload_base_kbits as u64, config.dry_run)
     {
         warn!("Failed to restore upload shaper rate: {error}");
     }
@@ -319,7 +336,13 @@ fn run(config: Config) -> anyhow::Result<()> {
         event_metrics: event_metrics.clone(),
     };
 
-    let (down_qdisc, up_qdisc) = initialize_shaper(&config)?;
+    let mut main_traffic_control = traffic_control_backend();
+    if main_traffic_control.is_observe_only() {
+        warn!(
+            "Traffic control is observe-only on this platform; requested rate changes will not be applied."
+        );
+    }
+    let (down_shaper, up_shaper) = initialize_shaper(&config, &mut main_traffic_control)?;
 
     let err_tx = error_tx.clone();
     let listener_peers = Arc::clone(&reflector_peers);
@@ -448,7 +471,7 @@ fn run(config: Config) -> anyhow::Result<()> {
         let _ = handle.join();
     }
 
-    restore_shaper(&config, down_qdisc, up_qdisc);
+    restore_shaper(&config, &mut main_traffic_control, &down_shaper, &up_shaper);
 
     result
 }

src/netlink.rs

@@ -10,6 +10,8 @@ use netlink_bindings::{rt_link, tc};
 use netlink_socket2::NetlinkSocket;
 use thiserror::Error;
 
+use crate::platform::{InterfaceStats, InterfaceStatsProvider, TrafficControlBackend};
+
 #[derive(Debug, Error)]
 pub enum NetlinkError {
     #[error("Couldn't find interface `{0}`")]
@@ -34,12 +36,13 @@ pub enum NetlinkError {
     Utf8Error(#[from] Utf8Error),
 }
 
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub struct Qdisc {
     pub ifindex: i32,
     pub parent: u32,
 }
 
+#[derive(Debug, Default)]
 pub struct Netlink {}
 
 impl Netlink {
@@ -140,3 +143,30 @@ impl Netlink {
         Ok(())
     }
 }
+
+impl InterfaceStatsProvider for Netlink {
+    type Error = NetlinkError;
+
+    fn read_stats(&mut self, interface: &str) -> Result<InterfaceStats, Self::Error> {
+        let (rx_bytes, tx_bytes) = Self::get_interface_stats(interface)?;
+        Ok(InterfaceStats { rx_bytes, tx_bytes })
+    }
+}
+
+impl TrafficControlBackend for Netlink {
+    type Error = NetlinkError;
+    type Handle = Qdisc;
+
+    fn find_shaper(&mut self, interface: &str) -> Result<Self::Handle, Self::Error> {
+        Self::qdisc_from_ifname(interface)
+    }
+
+    fn set_rate(
+        &mut self,
+        shaper: &Self::Handle,
+        bandwidth_kbit: u64,
+        dry_run: bool,
+    ) -> Result<(), Self::Error> {
+        Self::set_qdisc_rate(*shaper, bandwidth_kbit, dry_run)
+    }
+}

src/pinger_icmp.rs

@@ -14,7 +14,7 @@ use crate::time::Time;
 use icmp_socket2::Icmpv4Message;
 use icmp_socket2::Icmpv4Packet;
 use icmp_socket2::packet::WithEchoRequest;
-use rustix::thread::ClockId;
+use rustix::time::ClockId;
 
 pub struct PingerICMPEchoListener {}
 

src/pinger_icmp_ts.rs

@@ -11,7 +11,7 @@ use crate::time::Time;
 use icmp_socket2::Icmpv4Message;
 use icmp_socket2::Icmpv4Packet;
 use icmp_socket2::packet::WithTimestampRequest;
-use rustix::thread::ClockId;
+use rustix::time::ClockId;
 use std::net::IpAddr;
 use std::time::Instant;
 

src/platform.rs

@@ -0,0 +1,181 @@
+// SPDX-FileCopyrightText: 2026-Present Nils Andreas Svee mailto:contact@lochnair.net (github @Lochnair)
+//
+// SPDX-License-Identifier: MPL-2.0
+
+#[cfg(any(not(target_os = "linux"), test))]
+use log::debug;
+#[cfg(any(not(target_os = "linux"), test))]
+use std::collections::HashMap;
+#[cfg(any(not(target_os = "linux"), test))]
+use std::convert::Infallible;
+use std::error::Error;
+#[cfg(any(not(any(target_os = "linux", target_os = "macos")), test))]
+use thiserror::Error;
+
+#[cfg(target_os = "linux")]
+use crate::netlink::Netlink;
+
+#[cfg(target_os = "macos")]
+mod macos;
+#[cfg(target_os = "macos")]
+pub use macos::MacOsInterfaceStats;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct InterfaceStats {
+    pub rx_bytes: u64,
+    pub tx_bytes: u64,
+}
+
+pub trait InterfaceStatsProvider: Send {
+    type Error: Error + Send + Sync + 'static;
+
+    fn read_stats(&mut self, interface: &str) -> Result<InterfaceStats, Self::Error>;
+}
+
+pub trait TrafficControlBackend: Send {
+    type Error: Error + Send + Sync + 'static;
+    type Handle: Send + 'static;
+
+    fn find_shaper(&mut self, interface: &str) -> Result<Self::Handle, Self::Error>;
+
+    fn set_rate(
+        &mut self,
+        shaper: &Self::Handle,
+        bandwidth_kbit: u64,
+        dry_run: bool,
+    ) -> Result<(), Self::Error>;
+
+    fn is_observe_only(&self) -> bool {
+        false
+    }
+}
+
+#[cfg(any(not(any(target_os = "linux", target_os = "macos")), test))]
+#[derive(Debug, Default)]
+pub struct UnsupportedInterfaceStats;
+
+#[cfg(any(not(any(target_os = "linux", target_os = "macos")), test))]
+#[derive(Debug, Error, PartialEq, Eq)]
+#[error("interface statistics are unsupported on target OS `{target_os}`")]
+pub struct UnsupportedInterfaceStatsError {
+    target_os: &'static str,
+}
+
+#[cfg(any(not(any(target_os = "linux", target_os = "macos")), test))]
+impl InterfaceStatsProvider for UnsupportedInterfaceStats {
+    type Error = UnsupportedInterfaceStatsError;
+
+    fn read_stats(&mut self, _: &str) -> Result<InterfaceStats, Self::Error> {
+        Err(UnsupportedInterfaceStatsError {
+            target_os: std::env::consts::OS,
+        })
+    }
+}
+
+#[cfg(any(not(target_os = "linux"), test))]
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct ObserveOnlyShaper {
+    interface: String,
+}
+
+#[cfg(any(not(target_os = "linux"), test))]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+struct ObserveOnlyRequest {
+    bandwidth_kbit: u64,
+    dry_run: bool,
+}
+
+#[cfg(any(not(target_os = "linux"), test))]
+#[derive(Debug, Default)]
+pub struct ObserveOnlyTrafficControl {
+    last_requests: HashMap<String, ObserveOnlyRequest>,
+}
+
+#[cfg(any(not(target_os = "linux"), test))]
+impl TrafficControlBackend for ObserveOnlyTrafficControl {
+    type Error = Infallible;
+    type Handle = ObserveOnlyShaper;
+
+    fn find_shaper(&mut self, interface: &str) -> Result<Self::Handle, Self::Error> {
+        Ok(ObserveOnlyShaper {
+            interface: interface.to_string(),
+        })
+    }
+
+    fn set_rate(
+        &mut self,
+        shaper: &Self::Handle,
+        bandwidth_kbit: u64,
+        dry_run: bool,
+    ) -> Result<(), Self::Error> {
+        debug!(
+            "Observe-only traffic control requested rate {} kbit/s for interface {} (dry_run={})",
+            bandwidth_kbit, shaper.interface, dry_run
+        );
+        self.last_requests.insert(
+            shaper.interface.clone(),
+            ObserveOnlyRequest {
+                bandwidth_kbit,
+                dry_run,
+            },
+        );
+        Ok(())
+    }
+
+    fn is_observe_only(&self) -> bool {
+        true
+    }
+}
+
+#[cfg(test)]
+#[derive(Debug, Default)]
+pub struct UnsupportedTrafficControl;
+
+#[cfg(test)]
+#[derive(Debug, PartialEq, Eq)]
+pub struct UnsupportedShaper;
+
+#[cfg(test)]
+#[derive(Debug, Error, PartialEq, Eq)]
+#[error("traffic control is unsupported on target OS `{target_os}`")]
+pub struct UnsupportedTrafficControlError {
+    target_os: &'static str,
+}
+
+#[cfg(test)]
+impl TrafficControlBackend for UnsupportedTrafficControl {
+    type Error = UnsupportedTrafficControlError;
+    type Handle = UnsupportedShaper;
+
+    fn find_shaper(&mut self, _: &str) -> Result<Self::Handle, Self::Error> {
+        Err(UnsupportedTrafficControlError {
+            target_os: std::env::consts::OS,
+        })
+    }
+
+    fn set_rate(&mut self, _: &UnsupportedShaper, _: u64, _: bool) -> Result<(), Self::Error> {
+        Err(UnsupportedTrafficControlError {
+            target_os: std::env::consts::OS,
+        })
+    }
+}
+
+#[cfg(target_os = "linux")]
+pub type PlatformInterfaceStats = Netlink;
+#[cfg(target_os = "macos")]
+pub type PlatformInterfaceStats = MacOsInterfaceStats;
+#[cfg(not(any(target_os = "linux", target_os = "macos")))]
+pub type PlatformInterfaceStats = UnsupportedInterfaceStats;
+
+#[cfg(target_os = "linux")]
+pub type PlatformTrafficControl = Netlink;
+#[cfg(not(target_os = "linux"))]
+pub type PlatformTrafficControl = ObserveOnlyTrafficControl;
+
+pub fn interface_stats_provider() -> PlatformInterfaceStats {
+    PlatformInterfaceStats::default()
+}
+
+pub fn traffic_control_backend() -> PlatformTrafficControl {
+    PlatformTrafficControl::default()
+}

src/platform/macos.rs

@@ -0,0 +1,199 @@
+// SPDX-FileCopyrightText: 2026-Present Nils Andreas Svee mailto:contact@lochnair.net (github @Lochnair)
+//
+// SPDX-License-Identifier: MPL-2.0
+
+use std::ffi::{CString, NulError};
+use std::io;
+use std::mem::size_of;
+use std::ptr;
+
+use thiserror::Error;
+
+use super::{InterfaceStats, InterfaceStatsProvider};
+
+const ROUTE_MESSAGE_PREFIX_LEN: usize = size_of::<libc::c_ushort>() + 2;
+const SYSCTL_FETCH_ATTEMPTS: usize = 3;
+
+#[derive(Debug, Error)]
+pub enum MacOsInterfaceStatsError {
+    #[error("interface name contains a NUL byte")]
+    InterfaceNameContainsNul(#[source] NulError),
+
+    #[error("interface `{interface}` was not found")]
+    InterfaceNotFound {
+        interface: String,
+        #[source]
+        source: io::Error,
+    },
+
+    #[error("sysctl failed while {operation}")]
+    Sysctl {
+        operation: &'static str,
+        #[source]
+        source: io::Error,
+    },
+
+    #[error("malformed route-message response: {0}")]
+    MalformedResponse(String),
+
+    #[error("no RTM_IFINFO2 statistics returned for interface index {interface_index}")]
+    NoInterfaceStats { interface_index: libc::c_uint },
+}
+
+#[derive(Debug, Default)]
+pub struct MacOsInterfaceStats;
+
+impl InterfaceStatsProvider for MacOsInterfaceStats {
+    type Error = MacOsInterfaceStatsError;
+
+    fn read_stats(&mut self, interface: &str) -> Result<InterfaceStats, Self::Error> {
+        let interface_name =
+            CString::new(interface).map_err(MacOsInterfaceStatsError::InterfaceNameContainsNul)?;
+        // SAFETY: `interface_name` is a live, NUL-terminated C string for the duration of the call.
+        let interface_index = unsafe { libc::if_nametoindex(interface_name.as_ptr()) };
+        if interface_index == 0 {
+            return Err(MacOsInterfaceStatsError::InterfaceNotFound {
+                interface: interface.to_string(),
+                source: io::Error::last_os_error(),
+            });
+        }
+
+        let response = route_interface_list(interface_index)?;
+        parse_route_messages(&response, interface_index)
+    }
+}
+
+fn route_interface_list(
+    interface_index: libc::c_uint,
+) -> Result<Vec<u8>, MacOsInterfaceStatsError> {
+    let mut mib = [
+        libc::CTL_NET,
+        libc::PF_ROUTE,
+        0,
+        0,
+        libc::NET_RT_IFLIST2,
+        interface_index as libc::c_int,
+    ];
+
+    for attempt in 0..SYSCTL_FETCH_ATTEMPTS {
+        let mut required_len = 0;
+        // SAFETY: `mib` has the declared six elements, `required_len` is writable, and the
+        // null data pointers request only the response size without reading or writing data.
+        let size_result = unsafe {
+            libc::sysctl(
+                mib.as_mut_ptr(),
+                mib.len() as libc::c_uint,
+                ptr::null_mut(),
+                &mut required_len,
+                ptr::null_mut(),
+                0,
+            )
+        };
+        if size_result != 0 {
+            return Err(MacOsInterfaceStatsError::Sysctl {
+                operation: "querying the interface-list buffer size",
+                source: io::Error::last_os_error(),
+            });
+        }
+
+        let mut response = vec![0_u8; required_len];
+        let mut returned_len = required_len;
+        // SAFETY: `response` owns `required_len` initialized bytes, `returned_len` describes
+        // that allocation, and all other pointers remain valid for the duration of the call.
+        let fetch_result = unsafe {
+            libc::sysctl(
+                mib.as_mut_ptr(),
+                mib.len() as libc::c_uint,
+                response.as_mut_ptr().cast(),
+                &mut returned_len,
+                ptr::null_mut(),
+                0,
+            )
+        };
+        if fetch_result == 0 {
+            if returned_len > response.len() {
+                return Err(MacOsInterfaceStatsError::MalformedResponse(format!(
+                    "sysctl returned length {returned_len} for a {}-byte buffer",
+                    response.len()
+                )));
+            }
+            response.truncate(returned_len);
+            return Ok(response);
+        }
+
+        let source = io::Error::last_os_error();
+        let buffer_too_small = matches!(source.raw_os_error(), Some(libc::ENOMEM | libc::ENOBUFS));
+        if !buffer_too_small || attempt + 1 == SYSCTL_FETCH_ATTEMPTS {
+            return Err(MacOsInterfaceStatsError::Sysctl {
+                operation: "fetching the interface list",
+                source,
+            });
+        }
+    }
+
+    unreachable!("the bounded sysctl retry loop always returns")
+}
+
+fn parse_route_messages(
+    response: &[u8],
+    requested_interface_index: libc::c_uint,
+) -> Result<InterfaceStats, MacOsInterfaceStatsError> {
+    let mut offset = 0;
+
+    while offset < response.len() {
+        let remaining = response.len() - offset;
+        if remaining < ROUTE_MESSAGE_PREFIX_LEN {
+            return Err(MacOsInterfaceStatsError::MalformedResponse(format!(
+                "truncated route-message prefix at offset {offset}: {remaining} bytes remain"
+            )));
+        }
+
+        let message_len = usize::from(u16::from_ne_bytes([response[offset], response[offset + 1]]));
+        if message_len < ROUTE_MESSAGE_PREFIX_LEN {
+            return Err(MacOsInterfaceStatsError::MalformedResponse(format!(
+                "route message at offset {offset} has implausible length {message_len}"
+            )));
+        }
+
+        let message_end = offset.checked_add(message_len).ok_or_else(|| {
+            MacOsInterfaceStatsError::MalformedResponse(format!(
+                "route message length overflows at offset {offset}"
+            ))
+        })?;
+        if message_end > response.len() {
+            return Err(MacOsInterfaceStatsError::MalformedResponse(format!(
+                "route message at offset {offset} declares length {message_len}, exceeding the {}-byte response",
+                response.len()
+            )));
+        }
+
+        let message_type = response[offset + 3];
+        if message_type == libc::RTM_IFINFO2 as u8 {
+            if message_len < size_of::<libc::if_msghdr2>() {
+                return Err(MacOsInterfaceStatsError::MalformedResponse(format!(
+                    "RTM_IFINFO2 message at offset {offset} has length {message_len}, smaller than {}",
+                    size_of::<libc::if_msghdr2>()
+                )));
+            }
+
+            // SAFETY: the bounds checks above prove that a complete `if_msghdr2` lies within
+            // `response`; route messages are not guaranteed to have Rust alignment, so the value
+            // is copied with `read_unaligned` instead of creating a reference into the byte slice.
+            let header = unsafe {
+                ptr::read_unaligned(response.as_ptr().add(offset).cast::<libc::if_msghdr2>())
+            };
+            if libc::c_uint::from(header.ifm_index) == requested_interface_index {
+                return Ok(InterfaceStats {
+                    rx_bytes: header.ifm_data.ifi_ibytes,
+                    tx_bytes: header.ifm_data.ifi_obytes,
+                });
+            }
+        }
+
+        offset = message_end;
+    }
+
+    Err(MacOsInterfaceStatsError::NoInterfaceStats {
+        interface_index: requested_interface_index,
+    })
+}

src/ratecontroller.rs

@@ -7,13 +7,16 @@
 
 use crate::SHUTDOWN;
 use crate::metrics::{Metric, MetricsSender};
-use crate::netlink::{Netlink, NetlinkError, Qdisc};
+use crate::platform::{
+    InterfaceStatsProvider, PlatformInterfaceStats, PlatformTrafficControl, TrafficControlBackend,
+    interface_stats_provider, traffic_control_backend,
+};
 use crate::time::Time;
 use crate::util::{ArcMutex, ArcRwLock, MutexExt, RwLockExt};
 use crate::{Config, ReflectorStats};
 use flume::Sender;
 use log::{debug, info, warn};
-use rustix::thread::ClockId;
+use rustix::time::ClockId;
 use std::collections::HashMap;
 use std::fs::File;
 use std::io::Write;
@@ -21,7 +24,6 @@ use std::net::IpAddr;
 use std::sync::atomic::Ordering;
 use std::thread::sleep;
 use std::time::{Duration, Instant};
-use thiserror::Error;
 
 #[derive(Copy, Clone, Debug, PartialEq)]
 enum Direction {
@@ -29,12 +31,6 @@ enum Direction {
     Up,
 }
 
-#[derive(Debug, Error)]
-pub enum RatecontrolError {
-    #[error("Netlink error")]
-    Netlink(#[from] NetlinkError),
-}
-
 #[derive(Copy, Clone, Debug)]
 pub enum StatsDirection {
     RX,
@@ -51,34 +47,36 @@ fn generate_initial_speeds(base_speed: f64, size: u32) -> Vec<f64> {
     rates
 }
 
-fn get_interface_stats(
-    config: &Config,
+fn get_interface_stats<S: InterfaceStatsProvider>(
+    stats_provider: &mut S,
+    download_interface: &str,
+    upload_interface: &str,
     down_direction: StatsDirection,
     up_direction: StatsDirection,
-) -> Result<(i128, i128), RatecontrolError> {
-    let (down_rx, down_tx) = Netlink::get_interface_stats(config.download_interface.as_str())?;
-    let (up_rx, up_tx) = Netlink::get_interface_stats(config.upload_interface.as_str())?;
+) -> Result<(i128, i128), S::Error> {
+    let down = stats_provider.read_stats(download_interface)?;
+    let up = stats_provider.read_stats(upload_interface)?;
 
     let rx_bytes = match down_direction {
-        StatsDirection::RX => down_rx,
-        StatsDirection::TX => down_tx,
+        StatsDirection::RX => down.rx_bytes,
+        StatsDirection::TX => down.tx_bytes,
     };
 
     let tx_bytes = match up_direction {
-        StatsDirection::RX => up_rx,
-        StatsDirection::TX => up_tx,
+        StatsDirection::RX => up.rx_bytes,
+        StatsDirection::TX => up.tx_bytes,
     };
 
     Ok((rx_bytes.into(), tx_bytes.into()))
 }
 
 #[derive(Clone, Debug)]
-struct State {
+struct State<H> {
     current_bytes: i128,
     current_rate: f64,
     delta_stat: f64,
     deltas: Vec<f64>,
-    qdisc: Qdisc,
+    shaper: H,
     load: f64,
     next_rate: f64,
     nrate: usize,
@@ -88,8 +86,8 @@ struct State {
     utilisation: f64,
 }
 
-impl State {
-    fn new(qdisc: Qdisc, previous_bytes: i128, safe_rates: Vec<f64>) -> Self {
+impl<H> State<H> {
+    fn new(shaper: H, previous_bytes: i128, safe_rates: Vec<f64>) -> Self {
         State {
             current_bytes: 0,
             current_rate: 0.0,
@@ -98,7 +96,7 @@ impl State {
             load: 0.0,
             next_rate: 0.0,
             nrate: 0,
-            qdisc,
+            shaper,
             previous_bytes,
             prev_t: Instant::now(),
             safe_rates,
@@ -107,20 +105,84 @@ impl State {
     }
 }
 
-pub struct Ratecontroller {
+pub struct Ratecontroller<S: InterfaceStatsProvider, T: TrafficControlBackend> {
     config: Config,
     down_direction: StatsDirection,
     owd_baseline: ArcMutex<HashMap<IpAddr, ReflectorStats>>,
     owd_recent: ArcMutex<HashMap<IpAddr, ReflectorStats>>,
     reflectors_lock: ArcRwLock<Vec<IpAddr>>,
     reselect_trigger: Sender<bool>,
-    state_dl: State,
-    state_ul: State,
+    state_dl: State<T::Handle>,
+    state_ul: State<T::Handle>,
+    stats_provider: S,
+    traffic_control: T,
     up_direction: StatsDirection,
     metrics: MetricsSender,
 }
 
-impl Ratecontroller {
+impl<S: InterfaceStatsProvider, T: TrafficControlBackend> Ratecontroller<S, T> {
+    fn new_with_backends(
+        config: Config,
+        owd_baseline: ArcMutex<HashMap<IpAddr, ReflectorStats>>,
+        owd_recent: ArcMutex<HashMap<IpAddr, ReflectorStats>>,
+        reflectors_lock: ArcRwLock<Vec<IpAddr>>,
+        reselect_trigger: Sender<bool>,
+        down_direction: StatsDirection,
+        up_direction: StatsDirection,
+        metrics: MetricsSender,
+        mut stats_provider: S,
+        mut traffic_control: T,
+    ) -> anyhow::Result<Self> {
+        let dl_shaper = traffic_control.find_shaper(config.download_interface.as_str())?;
+        let dl_safe_rates =
+            generate_initial_speeds(config.download_base_kbits, config.speed_hist_size);
+        let ul_shaper = traffic_control.find_shaper(config.upload_interface.as_str())?;
+        let ul_safe_rates =
+            generate_initial_speeds(config.upload_base_kbits, config.speed_hist_size);
+
+        let (cur_rx, cur_tx) = get_interface_stats(
+            &mut stats_provider,
+            &config.download_interface,
+            &config.upload_interface,
+            down_direction,
+            up_direction,
+        )?;
+
+        Ok(Self {
+            config,
+            down_direction,
+            owd_baseline,
+            owd_recent,
+            reflectors_lock,
+            reselect_trigger,
+            state_dl: State::new(dl_shaper, cur_rx, dl_safe_rates),
+            state_ul: State::new(ul_shaper, cur_tx, ul_safe_rates),
+            stats_provider,
+            traffic_control,
+            up_direction,
+            metrics,
+        })
+    }
+
+    fn request_initial_rates(&mut self) -> anyhow::Result<()> {
+        // Set rates to 60% of base rate to make sure we start with sane baselines.
+        self.state_dl.current_rate = self.config.download_base_kbits * 0.6;
+        self.state_ul.current_rate = self.config.upload_base_kbits * 0.6;
+
+        self.traffic_control.set_rate(
+            &self.state_dl.shaper,
+            self.state_dl.current_rate.round() as u64,
+            self.config.dry_run,
+        )?;
+        self.traffic_control.set_rate(
+            &self.state_ul.shaper,
+            self.state_ul.current_rate.round() as u64,
+            self.config.dry_run,
+        )?;
+
+        Ok(())
+    }
+
     fn calculate_rate(&mut self, direction: Direction) -> anyhow::Result<()> {
         let (base_rate, delay_ms, min_rate, state) = if direction == Direction::Down {
             (
@@ -251,7 +313,9 @@ impl Ratecontroller {
 
         Ok(())
     }
+}
 
+impl Ratecontroller<PlatformInterfaceStats, PlatformTrafficControl> {
     pub fn new(
         config: Config,
         owd_baseline: ArcMutex<HashMap<IpAddr, ReflectorStats>>,
@@ -262,49 +326,29 @@ impl Ratecontroller {
         up_direction: StatsDirection,
         metrics: MetricsSender,
     ) -> anyhow::Result<Self> {
-        let dl_qdisc = Netlink::qdisc_from_ifname(config.download_interface.as_str())?;
-        let dl_safe_rates =
-            generate_initial_speeds(config.download_base_kbits, config.speed_hist_size);
-        let ul_qdisc = Netlink::qdisc_from_ifname(config.upload_interface.as_str())?;
-        let ul_safe_rates =
-            generate_initial_speeds(config.upload_base_kbits, config.speed_hist_size);
-
-        let (cur_rx, cur_tx) = get_interface_stats(&config, down_direction, up_direction)?;
-
-        Ok(Self {
+        Self::new_with_backends(
             config,
-            down_direction,
             owd_baseline,
             owd_recent,
             reflectors_lock,
             reselect_trigger,
-            state_dl: State::new(dl_qdisc, cur_rx, dl_safe_rates),
-            state_ul: State::new(ul_qdisc, cur_tx, ul_safe_rates),
+            down_direction,
             up_direction,
             metrics,
-        })
+            interface_stats_provider(),
+            traffic_control_backend(),
+        )
     }
+}
 
+impl<S: InterfaceStatsProvider, T: TrafficControlBackend> Ratecontroller<S, T> {
     pub fn run(&mut self) -> anyhow::Result<()> {
         let sleep_time = Duration::from_secs_f64(self.config.min_change_interval);
 
         let mut lastchg_t = Instant::now();
         let mut lastdump_t = Instant::now();
 
-        // set qdisc rates to 60% of base rate to make sure we start with sane baselines
-        self.state_dl.current_rate = self.config.download_base_kbits * 0.6;
-        self.state_ul.current_rate = self.config.upload_base_kbits * 0.6;
-
-        Netlink::set_qdisc_rate(
-            self.state_dl.qdisc,
-            self.state_dl.current_rate.round() as u64,
-            self.config.dry_run,
-        )?;
-        Netlink::set_qdisc_rate(
-            self.state_ul.qdisc,
-            self.state_ul.current_rate.round() as u64,
-            self.config.dry_run,
-        )?;
+        self.request_initial_rates()?;
 
         let mut speed_hist_fd: Option<File> = None;
         let mut speed_hist_fd_inner: File;
@@ -349,21 +393,13 @@ impl Ratecontroller {
                 // if it's been long enough, and the stats indicate needing to change speeds
                 // change speeds here
 
-                (self.state_dl.current_bytes, self.state_ul.current_bytes) =
-                    get_interface_stats(&self.config, self.down_direction, self.up_direction)?;
-                if self.state_dl.current_bytes == -1 || self.state_ul.current_bytes == -1 {
-                    warn!(
-                        "One or both Netlink stats could not be read. Skipping rate control algorithm"
-                    );
-                    self.metrics.send(Metric::Event {
-                        name: "netlink_read_failure",
-                        reason: "",
-                        reflector: None,
-                        tags: &[],
-                    });
-                    continue;
-                }
-
+                (self.state_dl.current_bytes, self.state_ul.current_bytes) = get_interface_stats(
+                    &mut self.stats_provider,
+                    &self.config.download_interface,
+                    &self.config.upload_interface,
+                    self.down_direction,
+                    self.up_direction,
+                )?;
                 self.update_deltas()?;
 
                 if self.state_dl.deltas.is_empty() || self.state_ul.deltas.is_empty() {
@@ -377,13 +413,13 @@ impl Ratecontroller {
                     self.state_dl.next_rate = self.config.download_min_kbits;
                     self.state_ul.next_rate = self.config.upload_min_kbits;
 
-                    Netlink::set_qdisc_rate(
-                        self.state_dl.qdisc,
+                    self.traffic_control.set_rate(
+                        &self.state_dl.shaper,
                         self.state_dl.next_rate as u64,
                         self.config.dry_run,
                     )?;
-                    Netlink::set_qdisc_rate(
-                        self.state_ul.qdisc,
+                    self.traffic_control.set_rate(
+                        &self.state_ul.shaper,
                         self.state_ul.next_rate as u64,
                         self.config.dry_run,
                     )?;
@@ -400,22 +436,22 @@ impl Ratecontroller {
                     || self.state_ul.next_rate != self.state_ul.current_rate
                 {
                     info!(
-                        "Adjusting rates (D/U): {} / {} kbit/s",
+                        "Requesting rates (D/U): {} / {} kbit/s",
                         self.state_dl.next_rate as u64, self.state_ul.next_rate as u64
                     );
                 }
 
                 if self.state_dl.next_rate != self.state_dl.current_rate {
-                    Netlink::set_qdisc_rate(
-                        self.state_dl.qdisc,
+                    self.traffic_control.set_rate(
+                        &self.state_dl.shaper,
                         self.state_dl.next_rate as u64,
                         self.config.dry_run,
                     )?;
                 }
 
                 if self.state_ul.next_rate != self.state_ul.current_rate {
-                    Netlink::set_qdisc_rate(
-                        self.state_ul.qdisc,
+                    self.traffic_control.set_rate(
+                        &self.state_ul.shaper,
                         self.state_ul.next_rate as u64,
                         self.config.dry_run,
                     )?;

src/time.rs

@@ -3,8 +3,7 @@
 // SPDX-License-Identifier: MPL-2.0
 
 use rustix::fs::Timespec;
-use rustix::thread::ClockId;
-use rustix::time::clock_gettime;
+use rustix::time::{ClockId, clock_gettime};
 
 pub struct Time {
     time_s: u64,