implement client config reading

tuic-client/src/config.rs

@@ -1,19 +1,115 @@
+use crate::utils::{self, CongestionControl, UdpRelayMode};
 use lexopt::{Arg, Error as ArgumentError, Parser};
-use serde::Deserialize;
+use serde::{de::Error as DeError, Deserialize, Deserializer};
 use serde_json::Error as SerdeError;
-use std::{ffi::OsString, fs::File, io::Error as IoError};
+use std::{
+    env::ArgsOs,
+    fs::File,
+    io::Error as IoError,
+    net::{IpAddr, SocketAddr},
+    time::Duration,
+};
 use thiserror::Error;
 
+const HELP_MSG: &str = r#"
+Usage tuic-client [arguments]
+
+Arguments:
+    -c, --config <path>     Path to the config file (required)
+    -v, --version           Print the version
+    -h, --help              Print this help message
+"#;
+
 #[derive(Deserialize)]
 #[serde(deny_unknown_fields)]
-pub struct Config {}
+pub struct Config {
+    pub relay: Relay,
+    pub local: Local,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct Relay {
+    #[serde(deserialize_with = "deserialize_server")]
+    pub server: (String, u16),
+    pub token: String,
+    pub ip: Option<IpAddr>,
+    #[serde(default = "default::relay::certificates")]
+    pub certificates: Vec<String>,
+    #[serde(
+        default = "default::relay::udp_relay_mode",
+        deserialize_with = "utils::deserialize_from_str"
+    )]
+    pub udp_relay_mode: UdpRelayMode,
+    #[serde(
+        default = "default::relay::congestion_control",
+        deserialize_with = "utils::deserialize_from_str"
+    )]
+    pub congestion_control: CongestionControl,
+    #[serde(default = "default::relay::alpn")]
+    pub alpn: Vec<String>,
+    #[serde(default = "default::relay::zero_rtt_handshake")]
+    pub zero_rtt_handshake: bool,
+    #[serde(default = "default::relay::timeout")]
+    pub timeout: Duration,
+    #[serde(default = "default::relay::heartbeat")]
+    pub heartbeat: Duration,
+}
+
+#[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
+pub struct Local {
+    pub server: SocketAddr,
+    pub username: Option<String>,
+    pub password: Option<String>,
+    pub dual_stack: Option<bool>,
+    #[serde(default = "default::local::max_packet_size")]
+    pub max_packet_size: usize,
+}
+
+mod default {
+    pub mod relay {
+        use crate::utils::{CongestionControl, UdpRelayMode};
+        use std::time::Duration;
+
+        pub const fn certificates() -> Vec<String> {
+            Vec::new()
+        }
+
+        pub const fn udp_relay_mode() -> UdpRelayMode {
+            UdpRelayMode::Native
+        }
+
+        pub const fn congestion_control() -> CongestionControl {
+            CongestionControl::Cubic
+        }
+
+        pub const fn alpn() -> Vec<String> {
+            Vec::new()
+        }
+
+        pub const fn zero_rtt_handshake() -> bool {
+            false
+        }
+
+        pub const fn timeout() -> Duration {
+            Duration::from_secs(8)
+        }
+
+        pub const fn heartbeat() -> Duration {
+            Duration::from_secs(3)
+        }
+    }
+
+    pub mod local {
+        pub const fn max_packet_size() -> usize {
+            1500
+        }
+    }
+}
 
 impl Config {
-    pub fn parse<A>(args: A) -> Result<Self, ConfigError>
-    where
-        A: IntoIterator,
-        A::Item: Into<OsString>,
-    {
+    pub fn parse(args: ArgsOs) -> Result<Self, ConfigError> {
         let mut parser = Parser::from_iter(args);
         let mut path = None;
 
@@ -29,7 +125,7 @@ impl Config {
                 Arg::Short('v') | Arg::Long("version") => {
                     return Err(ConfigError::Version(env!("CARGO_PKG_VERSION")))
                 }
-                Arg::Short('h') | Arg::Long("help") => return Err(ConfigError::Help(todo!())),
+                Arg::Short('h') | Arg::Long("help") => return Err(ConfigError::Help(HELP_MSG)),
                 _ => return Err(ConfigError::Argument(arg.unexpected())),
             }
         }
@@ -44,9 +140,25 @@ impl Config {
     }
 }
 
+pub fn deserialize_server<'de, D>(deserializer: D) -> Result<(String, u16), D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let s = String::deserialize(deserializer)?;
+    let mut parts = s.split(':');
+
+    match (parts.next(), parts.next(), parts.next()) {
+        (Some(domain), Some(port), None) => port.parse().map_or_else(
+            |e| Err(DeError::custom(e)),
+            |port| Ok((domain.to_owned(), port)),
+        ),
+        _ => Err(DeError::custom("invalid server address")),
+    }
+}
+
 #[derive(Debug, Error)]
 pub enum ConfigError {
-    #[error("transparent")]
+    #[error(transparent)]
     Argument(#[from] ArgumentError),
     #[error("no config file specified")]
     NoConfig,
@@ -54,8 +166,8 @@ pub enum ConfigError {
     Version(&'static str),
     #[error("{0}")]
     Help(&'static str),
-    #[error("transparent")]
+    #[error(transparent)]
     Io(#[from] IoError),
-    #[error("transparent")]
+    #[error(transparent)]
     Serde(#[from] SerdeError),
 }

tuic-client/src/connection.rs

@@ -1,4 +1,9 @@
-use crate::{error::Error, socks5};
+use crate::{
+    config::Relay,
+    error::Error,
+    socks5::Server as Socks5Server,
+    utils::{ServerAddr, UdpRelayMode},
+};
 use bytes::Bytes;
 use once_cell::sync::OnceCell;
 use parking_lot::Mutex;
@@ -27,14 +32,36 @@ static CONNECTION: AsyncOnceCell<AsyncMutex<Connection>> = AsyncOnceCell::const_
 
 const DEFAULT_CONCURRENT_STREAMS: usize = 32;
 
-struct Endpoint {
+pub struct Endpoint {
     ep: QuinnEndpoint,
+    server: ServerAddr,
+    token: Vec<u8>,
+    udp_relay_mode: UdpRelayMode,
+    zero_rtt_handshake: bool,
+    timeout: Duration,
+    heartbeat: Duration,
 }
 
 impl Endpoint {
-    fn new() -> Result<Self, Error> {
-        let ep = QuinnEndpoint::client(SocketAddr::from(([0, 0, 0, 0], 0)))?;
-        Ok(Self { ep })
+    pub fn set_config(cfg: Relay) -> Result<(), Error> {
+        let ep = todo!();
+
+        let ep = Self {
+            ep,
+            server: ServerAddr::new(cfg.server.0, cfg.server.1, cfg.ip),
+            token: cfg.token.into_bytes(),
+            udp_relay_mode: cfg.udp_relay_mode,
+            zero_rtt_handshake: cfg.zero_rtt_handshake,
+            timeout: cfg.timeout,
+            heartbeat: cfg.heartbeat,
+        };
+
+        ENDPOINT
+            .set(Mutex::new(ep))
+            .map_err(|_| "endpoint already initialized")
+            .unwrap();
+
+        Ok(())
     }
 
     async fn connect(&self) -> Result<Connection, Error> {
@@ -75,8 +102,9 @@ impl Connection {
     pub async fn get() -> Result<Connection, Error> {
         let try_init_conn = async {
             ENDPOINT
-                .get_or_try_init(|| Endpoint::new().map(Mutex::new))
-                .map(|ep| ep.lock())?
+                .get()
+                .unwrap()
+                .lock()
                 .connect()
                 .await
                 .map(AsyncMutex::new)
@@ -170,7 +198,7 @@ impl Connection {
                         }
                         Address::SocketAddress(addr) => Socks5Address::SocketAddress(addr),
                     };
-                    socks5::recv_pkt(pkt, addr, assoc_id).await
+                    Socks5Server::recv_pkt(pkt, addr, assoc_id).await
                 }
                 Ok(None) => Ok(()),
                 Err(err) => Err(Error::from(err)),
@@ -208,7 +236,7 @@ impl Connection {
                         }
                         Address::SocketAddress(addr) => Socks5Address::SocketAddress(addr),
                     };
-                    socks5::recv_pkt(pkt, addr, assoc_id).await
+                    Socks5Server::recv_pkt(pkt, addr, assoc_id).await
                 }
                 Ok(None) => Ok(()),
                 Err(err) => Err(Error::from(err)),

tuic-client/src/main.rs

@@ -1,14 +1,20 @@
-use self::config::{Config, ConfigError};
+use socks5::Server;
+
+use self::{
+    config::{Config, ConfigError},
+    connection::Endpoint,
+};
 use std::{env, process};
 
 mod config;
 mod connection;
 mod error;
 mod socks5;
+mod utils;
 
 #[tokio::main]
 async fn main() {
-    let _cfg = match Config::parse(env::args_os()) {
+    let cfg = match Config::parse(env::args_os()) {
         Ok(cfg) => cfg,
         Err(ConfigError::Version(msg) | ConfigError::Help(msg)) => {
             println!("{msg}");
@@ -20,8 +26,21 @@ async fn main() {
         }
     };
 
-    if let Err(err) = socks5::start().await {
-        eprintln!("{err}");
-        process::exit(1);
+    match Endpoint::set_config(cfg.relay) {
+        Ok(()) => {}
+        Err(err) => {
+            eprintln!("{err}");
+            process::exit(1);
+        }
     }
+
+    match Server::set_config(cfg.local).await {
+        Ok(()) => {}
+        Err(err) => {
+            eprintln!("{err}");
+            process::exit(1);
+        }
+    }
+
+    Server::start().await;
 }

tuic-client/src/socks5.rs

@@ -1,12 +1,12 @@
-use crate::{connection::Connection as TuicConnection, error::Error};
+use crate::{config::Local, connection::Connection as TuicConnection, error::Error};
 use bytes::Bytes;
-use once_cell::sync::Lazy;
+use once_cell::sync::{Lazy, OnceCell};
 use parking_lot::Mutex;
 use socks5_proto::{Address, Reply};
 use socks5_server::{
     auth::NoAuth,
     connection::{associate, bind, connect},
-    Associate, AssociatedUdpSocket, Bind, Connect, Connection, Server,
+    Associate, AssociatedUdpSocket, Bind, Connect, Connection, Server as Socks5Server,
 };
 use std::{
     collections::HashMap,
@@ -24,183 +24,214 @@ use tokio::{
 use tokio_util::compat::FuturesAsyncReadCompatExt;
 use tuic::Address as TuicAddress;
 
+static SERVER: OnceCell<Server> = OnceCell::new();
 static NEXT_ASSOCIATE_ID: AtomicU16 = AtomicU16::new(0);
 static UDP_SESSIONS: Lazy<Mutex<HashMap<u16, Arc<AssociatedUdpSocket>>>> =
     Lazy::new(|| Mutex::new(HashMap::new()));
 
-pub async fn start() -> Result<(), Error> {
-    let server = Server::bind("127.0.0.1:5000", Arc::new(NoAuth)).await?;
+pub struct Server {
+    inner: Socks5Server,
+    dual_stack: Option<bool>,
+    max_packet_size: usize,
+}
 
-    while let Ok((conn, _)) = server.accept().await {
-        tokio::spawn(async move {
-            let res = match conn.handshake().await {
-                Ok(Connection::Associate(associate, addr)) => {
-                    handle_associate(associate, addr).await
+impl Server {
+    pub async fn set_config(cfg: Local) -> Result<(), Error> {
+        let server = Socks5Server::bind(cfg.server, Arc::new(NoAuth)).await?;
+
+        let server = Self {
+            inner: server,
+            dual_stack: cfg.dual_stack,
+            max_packet_size: cfg.max_packet_size,
+        };
+
+        SERVER
+            .set(server)
+            .map_err(|_| "socks5 server already initialized")
+            .unwrap();
+
+        Ok(())
+    }
+
+    pub async fn start() {
+        let server = SERVER.get().unwrap();
+
+        loop {
+            match server.inner.accept().await {
+                Ok((conn, _)) => {
+                    tokio::spawn(async move {
+                        let res = match conn.handshake().await {
+                            Ok(Connection::Associate(associate, addr)) => {
+                                Self::handle_associate(associate, addr).await
+                            }
+                            Ok(Connection::Bind(bind, addr)) => Self::handle_bind(bind, addr).await,
+                            Ok(Connection::Connect(connect, addr)) => {
+                                Self::handle_connect(connect, addr).await
+                            }
+                            Err(err) => Err(Error::from(err)),
+                        };
+
+                        match res {
+                            Ok(_) => {}
+                            Err(err) => eprintln!("{err}"),
+                        }
+                    });
                 }
-                Ok(Connection::Bind(bind, addr)) => handle_bind(bind, addr).await,
-                Ok(Connection::Connect(connect, addr)) => handle_connect(connect, addr).await,
-                Err(err) => Err(Error::from(err)),
-            };
-
-            match res {
-                Ok(_) => {}
                 Err(err) => eprintln!("{err}"),
             }
-        });
-    }
-
-    Ok(())
-}
-
-async fn handle_associate(
-    assoc: Associate<associate::NeedReply>,
-    _addr: Address,
-) -> Result<(), Error> {
-    let assoc_socket = UdpSocket::bind(SocketAddr::from((assoc.local_addr()?.ip(), 0)))
-        .await
-        .and_then(|socket| {
-            socket
-                .local_addr()
-                .map(|addr| (Arc::new(AssociatedUdpSocket::from((socket, 1500))), addr))
-        });
-
-    match assoc_socket {
-        Ok((assoc_socket, assoc_addr)) => {
-            let assoc = assoc
-                .reply(Reply::Succeeded, Address::SocketAddress(assoc_addr))
-                .await?;
-            send_pkt(assoc, assoc_socket).await
-        }
-        Err(err) => {
-            let mut assoc = assoc
-                .reply(Reply::GeneralFailure, Address::unspecified())
-                .await?;
-            let _ = assoc.shutdown().await;
-            Err(Error::from(err))
         }
     }
-}
 
-async fn handle_bind(bind: Bind<bind::NeedFirstReply>, _addr: Address) -> Result<(), Error> {
-    let mut conn = bind
-        .reply(Reply::CommandNotSupported, Address::unspecified())
-        .await?;
-    let _ = conn.shutdown().await;
-    Ok(())
-}
-
-async fn handle_connect(conn: Connect<connect::NeedReply>, addr: Address) -> Result<(), Error> {
-    let target_addr = match addr {
-        Address::DomainAddress(domain, port) => TuicAddress::DomainAddress(domain, port),
-        Address::SocketAddress(addr) => TuicAddress::SocketAddress(addr),
-    };
-
-    let relay = match TuicConnection::get().await {
-        Ok(conn) => conn.connect(target_addr).await,
-        Err(err) => Err(err),
-    };
-
-    match relay {
-        Ok(relay) => {
-            let mut relay = relay.compat();
-            let conn = conn.reply(Reply::Succeeded, Address::unspecified()).await;
-
-            match conn {
-                Ok(mut conn) => match io::copy_bidirectional(&mut conn, &mut relay).await {
-                    Ok(_) => Ok(()),
-                    Err(err) => {
-                        let _ = conn.shutdown().await;
-                        let _ = relay.shutdown().await;
-                        Err(Error::from(err))
-                    }
-                },
-                Err(err) => {
-                    let _ = relay.shutdown().await;
-                    Err(Error::from(err))
-                }
-            }
-        }
-        Err(err) => {
-            let mut conn = conn
-                .reply(Reply::GeneralFailure, Address::unspecified())
-                .await?;
-            let _ = conn.shutdown().await;
-            Err(err)
-        }
-    }
-}
-
-async fn send_pkt(
-    mut assoc: Associate<associate::Ready>,
-    assoc_socket: Arc<AssociatedUdpSocket>,
-) -> Result<(), Error> {
-    let assoc_id = NEXT_ASSOCIATE_ID.fetch_add(1, Ordering::AcqRel);
-    UDP_SESSIONS.lock().insert(assoc_id, assoc_socket.clone());
-    let mut connected = None;
-
-    async fn accept_pkt(
-        assoc_socket: &AssociatedUdpSocket,
-        connected: &mut Option<SocketAddr>,
-        assoc_id: u16,
+    async fn handle_associate(
+        assoc: Associate<associate::NeedReply>,
+        _addr: Address,
     ) -> Result<(), Error> {
-        let (pkt, frag, dst_addr, src_addr) = assoc_socket.recv_from().await?;
+        let assoc_socket = UdpSocket::bind(SocketAddr::from((assoc.local_addr()?.ip(), 0)))
+            .await
+            .and_then(|socket| {
+                socket
+                    .local_addr()
+                    .map(|addr| (Arc::new(AssociatedUdpSocket::from((socket, 1500))), addr))
+            });
 
-        if let Some(connected) = connected {
-            if connected != &src_addr {
-                Err(IoError::new(
-                    ErrorKind::Other,
-                    format!("invalid source address: {src_addr}"),
-                ))?;
+        match assoc_socket {
+            Ok((assoc_socket, assoc_addr)) => {
+                let assoc = assoc
+                    .reply(Reply::Succeeded, Address::SocketAddress(assoc_addr))
+                    .await?;
+                Self::send_pkt(assoc, assoc_socket).await
+            }
+            Err(err) => {
+                let mut assoc = assoc
+                    .reply(Reply::GeneralFailure, Address::unspecified())
+                    .await?;
+                let _ = assoc.shutdown().await;
+                Err(Error::from(err))
             }
-        } else {
-            assoc_socket.connect(src_addr).await?;
-            *connected = Some(src_addr);
         }
+    }
 
-        if frag != 0 {
-            Err(IoError::new(
-                ErrorKind::Other,
-                format!("fragmented packet is not supported"),
-            ))?;
-        }
+    async fn handle_bind(bind: Bind<bind::NeedFirstReply>, _addr: Address) -> Result<(), Error> {
+        let mut conn = bind
+            .reply(Reply::CommandNotSupported, Address::unspecified())
+            .await?;
+        let _ = conn.shutdown().await;
+        Ok(())
+    }
 
-        let target_addr = match dst_addr {
+    async fn handle_connect(conn: Connect<connect::NeedReply>, addr: Address) -> Result<(), Error> {
+        let target_addr = match addr {
             Address::DomainAddress(domain, port) => TuicAddress::DomainAddress(domain, port),
             Address::SocketAddress(addr) => TuicAddress::SocketAddress(addr),
         };
 
-        TuicConnection::get()
-            .await?
-            .packet(pkt, target_addr, assoc_id)
-            .await
-    }
+        let relay = match TuicConnection::get().await {
+            Ok(conn) => conn.connect(target_addr).await,
+            Err(err) => Err(err),
+        };
 
-    let res = tokio::select! {
-        res = assoc.wait_until_closed() => res,
-        _ = async { loop {
-            if let Err(err) = accept_pkt(&assoc_socket, &mut connected, assoc_id).await {
-                eprintln!("{err}");
+        match relay {
+            Ok(relay) => {
+                let mut relay = relay.compat();
+                let conn = conn.reply(Reply::Succeeded, Address::unspecified()).await;
+
+                match conn {
+                    Ok(mut conn) => match io::copy_bidirectional(&mut conn, &mut relay).await {
+                        Ok(_) => Ok(()),
+                        Err(err) => {
+                            let _ = conn.shutdown().await;
+                            let _ = relay.shutdown().await;
+                            Err(Error::from(err))
+                        }
+                    },
+                    Err(err) => {
+                        let _ = relay.shutdown().await;
+                        Err(Error::from(err))
+                    }
+                }
             }
-        }} => unreachable!(),
-    };
-
-    let _ = assoc.shutdown().await;
-    UDP_SESSIONS.lock().remove(&assoc_id);
-
-    match TuicConnection::get().await {
-        Ok(conn) => match conn.dissociate(assoc_id).await {
-            Ok(_) => {}
-            Err(err) => eprintln!("{err}"),
-        },
-        Err(err) => eprintln!("{err}"),
+            Err(err) => {
+                let mut conn = conn
+                    .reply(Reply::GeneralFailure, Address::unspecified())
+                    .await?;
+                let _ = conn.shutdown().await;
+                Err(err)
+            }
+        }
     }
 
-    Ok(res?)
-}
+    async fn send_pkt(
+        mut assoc: Associate<associate::Ready>,
+        assoc_socket: Arc<AssociatedUdpSocket>,
+    ) -> Result<(), Error> {
+        let assoc_id = NEXT_ASSOCIATE_ID.fetch_add(1, Ordering::AcqRel);
+        UDP_SESSIONS.lock().insert(assoc_id, assoc_socket.clone());
+        let mut connected = None;
 
-pub async fn recv_pkt(pkt: Bytes, addr: Address, assoc_id: u16) -> Result<(), Error> {
-    let sessions = UDP_SESSIONS.lock();
-    let Some(assoc_socket) = sessions.get(&assoc_id) else { unreachable!() };
-    assoc_socket.send(pkt, 0, addr).await?;
-    Ok(())
+        async fn accept_pkt(
+            assoc_socket: &AssociatedUdpSocket,
+            connected: &mut Option<SocketAddr>,
+            assoc_id: u16,
+        ) -> Result<(), Error> {
+            let (pkt, frag, dst_addr, src_addr) = assoc_socket.recv_from().await?;
+
+            if let Some(connected) = connected {
+                if connected != &src_addr {
+                    Err(IoError::new(
+                        ErrorKind::Other,
+                        format!("invalid source address: {src_addr}"),
+                    ))?;
+                }
+            } else {
+                assoc_socket.connect(src_addr).await?;
+                *connected = Some(src_addr);
+            }
+
+            if frag != 0 {
+                Err(IoError::new(
+                    ErrorKind::Other,
+                    format!("fragmented packet is not supported"),
+                ))?;
+            }
+
+            let target_addr = match dst_addr {
+                Address::DomainAddress(domain, port) => TuicAddress::DomainAddress(domain, port),
+                Address::SocketAddress(addr) => TuicAddress::SocketAddress(addr),
+            };
+
+            TuicConnection::get()
+                .await?
+                .packet(pkt, target_addr, assoc_id)
+                .await
+        }
+
+        let res = tokio::select! {
+            res = assoc.wait_until_closed() => res,
+            _ = async { loop {
+                if let Err(err) = accept_pkt(&assoc_socket, &mut connected, assoc_id).await {
+                    eprintln!("{err}");
+                }
+            }} => unreachable!(),
+        };
+
+        let _ = assoc.shutdown().await;
+        UDP_SESSIONS.lock().remove(&assoc_id);
+
+        match TuicConnection::get().await {
+            Ok(conn) => match conn.dissociate(assoc_id).await {
+                Ok(_) => {}
+                Err(err) => eprintln!("{err}"),
+            },
+            Err(err) => eprintln!("{err}"),
+        }
+
+        Ok(res?)
+    }
+
+    pub async fn recv_pkt(pkt: Bytes, addr: Address, assoc_id: u16) -> Result<(), Error> {
+        let sessions = UDP_SESSIONS.lock();
+        let Some(assoc_socket) = sessions.get(&assoc_id) else { unreachable!() };
+        assoc_socket.send(pkt, 0, addr).await?;
+        Ok(())
+    }
 }

tuic-client/src/utils.rs

@@ -0,0 +1,65 @@
+use serde::{de::Error as DeError, Deserialize, Deserializer};
+use std::{fmt::Display, net::IpAddr, str::FromStr};
+
+pub fn deserialize_from_str<'de, T, D>(deserializer: D) -> Result<T, D::Error>
+where
+    T: FromStr,
+    <T as FromStr>::Err: Display,
+    D: Deserializer<'de>,
+{
+    let s = String::deserialize(deserializer)?;
+    T::from_str(&s).map_err(DeError::custom)
+}
+
+pub struct ServerAddr {
+    domain: String,
+    port: u16,
+    ip: Option<IpAddr>,
+}
+
+impl ServerAddr {
+    pub fn new(domain: String, port: u16, ip: Option<IpAddr>) -> Self {
+        Self { domain, port, ip }
+    }
+}
+
+pub enum UdpRelayMode {
+    Native,
+    Quic,
+}
+
+impl FromStr for UdpRelayMode {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.eq_ignore_ascii_case("native") {
+            Ok(Self::Native)
+        } else if s.eq_ignore_ascii_case("quic") {
+            Ok(Self::Quic)
+        } else {
+            Err("invalid UDP relay mode")
+        }
+    }
+}
+
+pub enum CongestionControl {
+    Cubic,
+    NewReno,
+    Bbr,
+}
+
+impl FromStr for CongestionControl {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.eq_ignore_ascii_case("cubic") {
+            Ok(Self::Cubic)
+        } else if s.eq_ignore_ascii_case("new_reno") || s.eq_ignore_ascii_case("newreno") {
+            Ok(Self::NewReno)
+        } else if s.eq_ignore_ascii_case("bbr") {
+            Ok(Self::Bbr)
+        } else {
+            Err("invalid congestion control")
+        }
+    }
+}