Upgrade toolchain to rust 1.79.0

Signed-off-by: Jacob Kiers <code@kiers.eu>

.cargo/config.toml

@@ -0,0 +1,3 @@
+[profile.release]
+lto = "thin"
+strip = true

.drone.jsonnet

@@ -0,0 +1,92 @@
+local executableName = 'l4p';
+local build_image = 'img.kie.rs/jjkiers/rust-crossbuild:rust1.79.0-zig0.11.0-zig';
+
+local archs = [
+  { target: 'aarch64-unknown-linux-musl', short: 'arm64-musl' },
+  { target: 'x86_64-pc-windows-gnu', short: 'windows' },
+  { target: 'x86_64-unknown-linux-musl', short: 'amd64-musl' },
+];
+
+local getStepName(arch) = 'Build for ' + arch.short;
+
+local builtExecutableName(arch) = executableName + if std.length(std.findSubstr(arch.short, 'windows')) > 0 then '.exe' else '';
+local targetExecutableName(arch) = executableName + '-' + arch.target + if std.length(std.findSubstr(arch.short, 'windows')) > 0 then '.exe' else '';
+
+local getVolumeName(arch) = 'target-' + arch.target;
+local getLocalVolumes(arch) = [
+  {
+    name: getVolumeName(arch),
+    temp: {},
+  }
+  for arch in archs
+];
+
+local add_build_steps() = [
+  {
+    name: getStepName(arch),
+    image: build_image,
+    commands: [
+      'echo Hello World from Jsonnet on ' + arch.target + '!',
+      'cargo zigbuild --release --target ' + arch.target,
+      'cp target/' + arch.target + '/release/' + builtExecutableName(arch) + ' artifacts/' + targetExecutableName(arch),
+      'rm -rf target/' + arch.target + '/release/*',
+    ],
+    depends_on: ['Prepare'],
+    volumes: [{
+      name: getVolumeName(arch),
+      path: '/drone/src/target',
+    }],
+  }
+  for arch in archs
+];
+
+{
+  kind: 'pipeline',
+  type: 'docker',
+  name: 'default',
+  platform: {
+    arch: 'amd64',
+  },
+  steps:
+    [{
+      name: 'Prepare',
+      image: build_image,
+      commands: [
+        'mkdir artifacts',
+        'echo Using image: ' + build_image,
+        'cargo --version',
+        'rustc --version',
+      ],
+    }] +
+    add_build_steps() +
+    [
+      {
+        name: 'Show built artifacts',
+        image: build_image,
+        commands: [
+          'ls -lah artifacts',
+        ],
+        depends_on: [getStepName(a) for a in archs],
+      },
+      {
+        name: 'Create release on gitea',
+        image: 'plugins/gitea-release',
+        settings: {
+          api_key: {
+            from_secret: 'gitea_token',
+          },
+          base_url: 'https://code.kiers.eu',
+          files: 'artifacts/*',
+          checksum: 'sha256',
+        },
+        when: {
+          event: ['tag', 'promote'],
+        },
+        depends_on: ['Show built artifacts'],
+      },
+    ],
+
+  volumes: getLocalVolumes(archs),
+
+  image_pull_secrets: ['docker_private_repo'],
+}

.github/workflows/publish-binaries.yml

@@ -1,39 +0,0 @@
-on:
-  release:
-    types: [published]
-
-name: Publish binaries to release
-
-jobs:
-  publish:
-    name: Publish for ${{ matrix.os }}
-    runs-on: ${{ matrix.os }}
-
-    strategy:
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-        include:
-          - os: ubuntu-latest
-            artifact_name: fourth
-            asset_name: fourth-linux-amd64
-          - os: macos-latest
-            artifact_name: fourth
-            asset_name: fourth-macos-amd64
-          - os: windows-latest
-            artifact_name: fourth.exe
-            asset_name: fourth-windows-amd64.exe
-    
-    steps:
-      - uses: hecrj/setup-rust-action@master
-        with:
-          rust-version: stable
-      - uses: actions/checkout@v2
-      - name: Build
-        run: cargo build --release --locked
-      - name: Publish
-        uses: svenstaro/upload-release-action@v1-release
-        with:
-          repo_token: ${{ secrets.PUBLISH_TOKEN }}
-          file: target/release/${{ matrix.artifact_name }}
-          asset_name: ${{ matrix.asset_name }}
-          tag: ${{ github.ref }}

.github/workflows/rust.yml

@@ -1,24 +0,0 @@
-name: Rust
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-env:
-  CARGO_TERM_COLOR: always
-
-jobs:
-  build:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v2
-    - name: Upgrade Rust
-      run: rustup update
-    - name: Build
-      run: cargo build --verbose
-    - name: Run tests
-      run: cargo test --verbose

.gitignore

@@ -1 +1,4 @@
+/.idea
+/.vscode
 /target
+config.yaml

CHANGELOG.md

@@ -0,0 +1,42 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.1.9] - 2024-06-22
+
+### Deprecated
+
+The ability to run `l4p` without arguments is now deprecated. Please use 
+`l4p serve` going forward.
+
+### Added
+
+* Added self update functionality. Just run `l4p update` to use it.
+* Now keeping a change log in the `CHANGELOG.md` file.
+
+### Changed
+
+* Updated build pipeline to generate much smaller binaries
+
+-------
+
+## Previous versions
+
+[unreleased]: https://code.kiers.eu/jjkiers/layer4-proxy/compare/v0.1.9...HEAD
+[0.1.9]: https://code.kiers.eu/jjkiers/layer4-proxy/compare/v0.1.8...v0.1.9
+
+
+
+Types of changes:
+
+* `Added` for new features.
+* `Changed` for changes in existing functionality.
+* `Deprecated` for soon-to-be removed features.
+* `Removed` for now removed features.
+* `Fixed` for any bug fixes.
+* `Security` in case of vulnerabilities.

Cargo.toml

@@ -1,13 +1,13 @@
 [package]
-name = "fourth"
+name = "l4p"
-version = "0.1.5"
+version = "0.1.9"
 edition = "2021"
-authors = ["LI Rui <lr_cn@outlook.com>"]
+authors = ["Jacob Kiers <code@kiers.eu>"]
 license = "Apache-2.0"
 description = "Simple and fast layer 4 proxy in Rust"
 readme = "README.md"
-homepage = "https://github.com/KernelErr/fourth"
+homepage = "https://code.kiers.eu/jjkiers/layer4-proxy"
-repository = "https://github.com/KernelErr/fourth"
+repository = "https://code.kiers.eu/jjkiers/layer4-proxy"
 keywords = ["proxy", "network"]
 categories = ["web-programming"]
 
@@ -15,17 +15,26 @@ categories = ["web-programming"]
 
 exclude = [".*"]
 
+[[bin]]
+name = "l4p"
+path = "src/main.rs"
+
 [dependencies]
-log = "0.4"
+async-trait = "0.1.73"
-pretty_env_logger = "0.4"
+byte_string = "1"
-serde = { version = "1.0", features = ["derive"] }
+bytes = "1.1"
-serde_yaml = "0.8"
 futures = "0.3"
+log = "0.4"
+pico-args = "0.5.0"
+pretty_env_logger = "0.5"
+serde = { version = "1.0", features = ["derive"] }
+serde_yaml = "0.9.21"
+time = { version = "0.3.1", features = ["local-offset", "formatting"] }
 tls-parser = "0.11"
+tokio = { version = "1.0", features = ["full"] }
 url = "2.2.2"
 
-tokio = { version = "1.0", features = ["full"] }
+[dependencies.self_update]
-
+version = "0.40.0"
-bytes = "1.1"
+default-features = false
-kcp = "0.4"
+features = ["rustls"]
-byte_string = "1"

README-EN.md

@@ -1,70 +0,0 @@
-# Fourth
-
-> Hey, now we are on level 4!
-
-[![](https://img.shields.io/crates/v/fourth)](https://crates.io/crates/fourth) [![CI](https://img.shields.io/github/workflow/status/kernelerr/fourth/Rust)](https://github.com/KernelErr/fourth/actions/workflows/rust.yml)
-
-**Under heavy development, version 0.1 may update frequently**
-
-Fourth is a layer 4 proxy implemented by Rust to listen on specific ports and transfer TCP/KCP data to remote addresses(only TCP) according to configuration.
-
-## Features
-
-- Listen on specific port and proxy to local or remote port
-- SNI-based rule without terminating TLS connection
-- Allow KCP inbound(warning: untested)
-
-## Installation
-
-To gain best performance on your computer's architecture, please consider build the source code. First, you may need [Rust tool chain](https://rustup.rs/).
-
-```bash
-$ cd fourth
-$ cargo build --release
-```
-
-Binary file will be generated at `target/release/fourth`, or you can use `cargo install --path .` to install.
-
-Or you can use Cargo to install Fourth:
-
-```bash
-$ cargo install fourth
-```
-
-Or you can download binary file form the Release page.
-
-## Configuration
-
-Fourth will read yaml format configuration file from `/etc/fourth/config.yaml`, and you can set custom path to environment variable `FOURTH_CONFIG`, here is an minimal viable example:
-
-```yaml
-version: 1
-log: info
-
-servers:
-  proxy_server:
-    listen:
-      - "127.0.0.1:8081"
-    default: remote
-
-upstream:
-  remote: "tcp://www.remote.example.com:8082" # proxy to remote address
-```
-
-Built-in two upstreams: ban(terminate connection immediately), echo. For detailed configuration, check [this example](./example-config.yaml).
-
-## Performance Benchmark
-
-Tested on 4C2G server:
-
-Use fourth to proxy to Nginx(QPS of direct connection: ~120000): ~70000 req/s (Command: `wrk -t200 -c1000 -d120s --latency http://proxy-server:8081`)
-
-Use fourth to proxy to local iperf3: 8Gbps
-
-## Thanks
-
-- [tokio_kcp](https://github.com/Matrix-Zhang/tokio_kcp)
-
-## License
-
-Fourth is available under terms of Apache-2.0.

README.md

@@ -1,43 +1,39 @@
-# Fourth
+# l4p
 
-> 这一波在第四层。
+> Hey, now we are on level 4!
 
-[![](https://img.shields.io/crates/v/fourth)](https://crates.io/crates/fourth) [![CI](https://img.shields.io/github/workflow/status/kernelerr/fourth/Rust)](https://github.com/KernelErr/fourth/actions/workflows/rust.yml)
+![CI](https://drone-ci.kiers.eu/api/badges/jjkiers/layer4-proxy/status.svg)
 
-[English](/README-EN.md)
+`l4p` is a layer 4 proxy implemented by Rust to listen on specific ports and transfer TCP data to remote addresses (only TCP) according to the configuration.
 
-**积极开发中，0.1版本迭代可能较快**
+## Features
 
-Fourth是一个Rust实现的Layer 4代理，用于监听指定端口TCP/KCP流量，并根据规则转发到指定目标（目前只支持TCP）。
+- Listen on specific port and proxy to local or remote port
+- SNI-based rule without terminating TLS connection
+- DNS-based backend with periodic resolution
 
-## 功能
+## Installation
 
-- 监听指定端口代理到本地或远端指定端口
+To gain best performance on your computer's architecture, please consider build the source code. First, you may need [Rust tool chain](https://rustup.rs/).
-- 监听指定端口，通过TLS ClientHello消息中的SNI进行分流
-- 支持KCP入站（警告：未测试）
-
-## 安装方法
-
-为了确保获得您架构下的最佳性能，请考虑自行编译，首选需要确保您拥有[Rust工具链](https://rustup.rs/)。
 
 ```bash
-$ cd fourth
+$ cd l4p
 $ cargo build --release
 ```
 
-将在`target/release/fourth`生成二进制文件，您也可以使用`cargo install --path . `来安装二进制文件。
+Binary file will be generated at `target/release/l4p`, or you can use `cargo install --path .` to install.
 
-或者您也可以使用Cargo直接安装：
+Or you can use Cargo to install `l4p`:
 
 ```bash
-$ cargo install fourth
+$ cargo install l4p
 ```
 
-或者您也可以直接从Release中下载二进制文件。
+Or you can download binary file form the Release page.
 
-## 配置
+## Configuration
 
-Fourth使用yaml格式的配置文件，默认情况下会读取`/etc/fourth/config.yaml`，您也可以设置自定义路径到环境变量`FOURTH_CONFIG`，如下是一个最小有效配置：
+`l4p` will read yaml format configuration file from `/etc/l4p/l4p.yaml`, and you can set custom path to environment variable `L4P_CONFIG`, here is an minimal viable example:
 
 ```yaml
 version: 1
@@ -53,28 +49,16 @@ upstream:
   remote: "tcp://www.remote.example.com:8082" # proxy to remote address
 ```
 
-内置两个的upstream：ban（立即中断连接）、echo（返回读到的数据）。更详细的配置可以参考[示例配置](./example-config.yaml)。
+There are two upstreams built in:
+* Ban, which terminates the connection immediately
+* Echo, which reflects back with the input
 
-注意：[::]会默认同时绑定IPv4和IPv6。
+For detailed configuration, check [this example](./config.yaml.example).
 
-## 性能测试
+## Thanks
 
-在4C2G的服务器上测试：
+- [`fourth`](https://crates.io/crates/fourth), of which this is a heavily modified fork.
 
-使用Fourth代理到Nginx（直连QPS 120000）: ~70000req/s （测试命令：`wrk -t200 -c1000 -d120s --latency http://proxy-server:8081 `）
+## License
 
-使用Fourth代理到本地iperf3：8Gbps
+`l4p` is available under terms of Apache-2.0.
-
-## io_uring?
-
-尽管经过了很多尝试，我们发现目前一些Rust下面的io_uring实现存在问题，我们使用的io_uring库实现尽管在吞吐量上可以做到单线程20Gbps（相比之下Tokio仅有8Gbps），但在QPS上存在性能损失较大的问题。因此在有成熟的io_uring实现之前，我们仍然选择epoll。之后我们会持续关注相关进展。
-
-可能以后会为Linux高内核版本的用户提供可选的io_uring加速。
-
-## 感谢
-
-- [tokio_kcp](https://github.com/Matrix-Zhang/tokio_kcp)
-
-## 协议
-
-Fourth以Apache-2.0协议开源。

config.yaml.example

@@ -0,0 +1,21 @@
+version: 1
+log: debug
+
+servers:
+  first_server:
+    listen:
+      - "0.0.0.0:8443"
+      - "[::]:8443"
+    tls: true # Enable TLS features like SNI filtering
+    sni:
+      api.example.org: example-api
+      www.example.org: proxy
+    default: ban
+
+  second-server:
+    listen: [ "127.0.0.1:8080" ]
+    default: echo
+
+upstream:
+  proxy: "tcp://new-www.example.org:443" # Connect over IPv4 or IPv6 to new-www.example.org:443
+  example-api: "tcp6://api-v1.example.com:443" # Connect over IPv6 to api-v1.example.com:443

example-config.yaml

@@ -15,11 +15,6 @@ servers:
     listen:
       - "127.0.0.1:8081"
     default: remote
-  kcp_server:
-    protocol: kcp # default TCP
-    listen:
-      - "127.0.0.1:8082"
-    default: echo
 
 upstream:
   nginx: "tcp://127.0.0.1:8080"

l4p.service

@@ -0,0 +1,51 @@
+[Unit]
+Description=l4p - Layer 4 proxy
+
+After=network-online.target
+Wants=network-online.target
+
+[Install]
+WantedBy=default.target
+
+[Service]
+Type=simple
+
+# Allow read-only access to the config directory
+ReadOnlyPaths=/etc/l4p
+# Path to the binary
+ExecStart=/usr/local/bin/l4p
+
+# Needs CAP_NET_BIND_SERVICE in order to bind to lower ports
+# When using ports above 1024, these should be made empty
+AmbientCapabilities=CAP_NET_BIND_SERVICE
+CapabilityBoundingSet=CAP_NET_BIND_SERVICE
+
+# Run as a dynamic user
+DynamicUser=yes
+
+# Security
+PrivateTmp=yes
+PrivateDevices=yes
+ProtectSystem=strict
+ProtectHome=yes
+SystemCallFilter=@basic-io @file-system @network-io @system-service
+SystemCallFilter=~@privileged
+SystemCallFilter=~@resources
+NoNewPrivileges=yes
+ProtectProc=invisible
+RemoveIPC=yes
+RestrictAddressFamilies=AF_INET AF_INET6
+RestrictNamespaces=yes
+ProtectHostname=yes
+ProtectClock=yes
+ProtectKernelModules=yes
+ProtectKernelLogs=yes
+ProtectControlGroups=yes
+LockPersonality=yes
+MemoryDenyWriteExecute=yes
+RestrictRealtime=yes
+ProcSubset=pid
+UMask=0077
+SystemCallArchitectures=native
+RestrictSUIDSGID=yes
+ProtectKernelTunables=yes

src/config/config_v1.rs

@@ -1,4 +1,6 @@
-use log::{debug, warn};
+use crate::upstreams::ProxyToUpstream;
+use crate::upstreams::Upstream;
+use log::{debug, info, warn};
 use serde::Deserialize;
 use std::collections::{HashMap, HashSet};
 use std::fs::File;
@@ -6,12 +8,12 @@ use std::io::{Error as IOError, Read};
 use url::Url;
 
 #[derive(Debug, Clone)]
-pub struct Config {
+pub struct ConfigV1 {
-    pub base: ParsedConfig,
+    pub base: ParsedConfigV1,
 }
 
 #[derive(Debug, Default, Deserialize, Clone)]
-pub struct ParsedConfig {
+pub struct ParsedConfigV1 {
     pub version: i32,
     pub log: Option<String>,
     pub servers: HashMap<String, ServerConfig>,
@@ -34,19 +36,55 @@ pub struct ServerConfig {
     pub sni: Option<HashMap<String, String>>,
     pub default: Option<String>,
 }
+impl TryInto<ProxyToUpstream> for &str {
+    type Error = ConfigError;
 
-#[derive(Debug, Clone, Deserialize)]
+    fn try_into(self) -> Result<ProxyToUpstream, Self::Error> {
-pub enum Upstream {
+        let upstream_url = match Url::parse(self) {
-    Ban,
+            Ok(url) => url,
-    Echo,
+            Err(_) => {
-    Custom(CustomUpstream),
+                return Err(ConfigError::Custom(format!(
+                    "Invalid upstream url {}",
+                    self
+                )))
+            }
+        };
+
+        let upstream_host = match upstream_url.host_str() {
+            Some(host) => host,
+            None => {
+                return Err(ConfigError::Custom(format!(
+                    "Invalid upstream url {}",
+                    self
+                )))
+            }
+        };
+
+        let upstream_port = match upstream_url.port_or_known_default() {
+            Some(port) => port,
+            None => {
+                return Err(ConfigError::Custom(format!(
+                    "Invalid upstream url {}",
+                    self
+                )))
+            }
+        };
+
+        match upstream_url.scheme() {
+            "tcp" | "tcp4" | "tcp6" => {}
+            _ => {
+                return Err(ConfigError::Custom(format!(
+                    "Invalid upstream scheme {}",
+                    self
+                )))
+            }
         }
 
-#[derive(Debug, Clone, Deserialize)]
+        Ok(ProxyToUpstream::new(
-pub struct CustomUpstream {
+            format!("{}:{}", upstream_host, upstream_port),
-    pub name: String,
+            upstream_url.scheme().to_string(),
-    pub addr: String,
+        ))
-    pub protocol: String,
+    }
 }
 
 #[derive(Debug)]
@@ -56,18 +94,18 @@ pub enum ConfigError {
     Custom(String),
 }
 
-impl Config {
+impl ConfigV1 {
-    pub fn new(path: &str) -> Result<Config, ConfigError> {
+    pub fn new(path: &str) -> Result<ConfigV1, ConfigError> {
-        let base = (load_config(path))?;
+        let base = load_config(path)?;
 
-        Ok(Config { base })
+        Ok(ConfigV1 { base })
     }
 }
 
-fn load_config(path: &str) -> Result<ParsedConfig, ConfigError> {
+fn load_config(path: &str) -> Result<ParsedConfigV1, ConfigError> {
     let mut contents = String::new();
-    let mut file = (File::open(path))?;
+    let mut file = File::open(path)?;
-    (file.read_to_string(&mut contents))?;
+    file.read_to_string(&mut contents)?;
 
     let base: BaseConfig = serde_yaml::from_str(&contents)?;
 
@@ -81,66 +119,23 @@ fn load_config(path: &str) -> Result<ParsedConfig, ConfigError> {
     if !log_level.eq("disable") {
         std::env::set_var("FOURTH_LOG", log_level.clone());
         pretty_env_logger::init_custom_env("FOURTH_LOG");
-        debug!("Set log level to {}", log_level);
     }
 
+    info!("Using config file: {}", &path);
+    debug!("Set log level to {}", log_level);
     debug!("Config version {}", base.version);
 
     let mut parsed_upstream: HashMap<String, Upstream> = HashMap::new();
 
-    for (name, upstream) in base.upstream.iter() {
-        let upstream_url = match Url::parse(upstream) {
-            Ok(url) => url,
-            Err(_) => {
-                return Err(ConfigError::Custom(format!(
-                    "Invalid upstream url {}",
-                    upstream
-                )))
-            }
-        };
-
-        let upstream_host = match upstream_url.host_str() {
-            Some(host) => host,
-            None => {
-                return Err(ConfigError::Custom(format!(
-                    "Invalid upstream url {}",
-                    upstream
-                )))
-            }
-        };
-
-        let upsteam_port = match upstream_url.port_or_known_default() {
-            Some(port) => port,
-            None => {
-                return Err(ConfigError::Custom(format!(
-                    "Invalid upstream url {}",
-                    upstream
-                )))
-            }
-        };
-
-        if upstream_url.scheme() != "tcp" {
-            return Err(ConfigError::Custom(format!(
-                "Invalid upstream scheme {}",
-                upstream
-            )));
-        }
-
-        parsed_upstream.insert(
-            name.to_string(),
-            Upstream::Custom(CustomUpstream {
-                name: name.to_string(),
-                addr: format!("{}:{}", upstream_host, upsteam_port),
-                protocol: upstream_url.scheme().to_string(),
-            }),
-        );
-    }
-
     parsed_upstream.insert("ban".to_string(), Upstream::Ban);
-
     parsed_upstream.insert("echo".to_string(), Upstream::Echo);
 
-    let parsed = ParsedConfig {
+    for (name, upstream) in base.upstream.iter() {
+        let ups = upstream.as_str().try_into()?;
+        parsed_upstream.insert(name.to_string(), Upstream::Proxy(ups));
+    }
+
+    let parsed = ParsedConfigV1 {
         version: base.version,
         log: base.log,
         servers: base.servers,
@@ -150,7 +145,7 @@ fn load_config(path: &str) -> Result<ParsedConfig, ConfigError> {
     verify_config(parsed)
 }
 
-fn verify_config(config: ParsedConfig) -> Result<ParsedConfig, ConfigError> {
+fn verify_config(config: ParsedConfigV1) -> Result<ParsedConfigV1, ConfigError> {
     let mut used_upstreams: HashSet<String> = HashSet::new();
     let mut upstream_names: HashSet<String> = HashSet::new();
     let mut listen_addresses: HashSet<String> = HashSet::new();
@@ -224,10 +219,10 @@ mod tests {
 
     #[test]
     fn test_load_config() {
-        let config = Config::new("tests/config.yaml").unwrap();
+        let config = ConfigV1::new("tests/config.yaml").unwrap();
         assert_eq!(config.base.version, 1);
         assert_eq!(config.base.log.unwrap(), "disable");
-        assert_eq!(config.base.servers.len(), 5);
+        assert_eq!(config.base.servers.len(), 3);
         assert_eq!(config.base.upstream.len(), 3 + 2); // Add ban and echo upstreams
     }
 }

src/config/mod.rs

@@ -0,0 +1,3 @@
+mod config_v1;
+pub(crate) use config_v1::ConfigV1;
+pub(crate) use config_v1::ParsedConfigV1;

src/main.rs

@@ -1,18 +1,45 @@
 mod config;
-mod plugins;
 mod servers;
+mod update;
+mod upstreams;
 
-use crate::config::Config;
+use crate::config::ConfigV1;
 use crate::servers::Server;
 
-use log::{debug, error};
+use log::{debug, error, info};
-use std::env;
+use pico_args::Arguments;
+use std::path::PathBuf;
 
 fn main() {
-    let config_path =
+    let mut args = Arguments::from_env();
-        env::var("FOURTH_CONFIG").unwrap_or_else(|_| "/etc/fourth/config.yaml".to_string());
 
-    let config = match Config::new(&config_path) {
+    match args.subcommand().expect("Unexpected error").as_deref() {
+        Some("serve") => serve(),
+        Some("update") => update::update(),
+        Some(cmd) => {
+            eprintln!("Invalid command: {cmd}");
+            std::process::exit(1);
+        }
+        None => {
+            eprintln!("Calling l4p without argument is deprecated now. Please use: l4p serve");
+            serve();
+        }
+    }
+}
+
+fn serve() {
+    let config_path = match find_config() {
+        Ok(p) => p,
+        Err(paths) => {
+            println!("Could not find config file. Tried paths:");
+            for p in paths {
+                println!("- {}", p);
+            }
+            std::process::exit(1);
+        }
+    };
+
+    let config = match ConfigV1::new(&config_path) {
         Ok(config) => config,
         Err(e) => {
             println!("Could not load config: {:?}", e);
@@ -21,9 +48,43 @@ fn main() {
     };
     debug!("{:?}", config);
 
-    let mut server = Server::new(config.base);
+    let mut server = Server::new_from_v1_config(config.base);
     debug!("{:?}", server);
 
     let _ = server.run();
     error!("Server ended with errors");
 }
+
+fn find_config() -> Result<String, Vec<String>> {
+    let possible_locations = ["/etc/l4p", ""];
+    let possible_names = ["l4p.yaml", "config.yaml"];
+
+    let mut tried_paths = Vec::<String>::new();
+    let mut possible_paths = Vec::<PathBuf>::new();
+
+    if let Ok(env_path) = std::env::var("L4P_CONFIG") {
+        possible_paths.push(PathBuf::from(env_path));
+    }
+
+    possible_paths.append(
+        &mut possible_locations
+            .iter()
+            .flat_map(|&path| {
+                possible_names
+                    .iter()
+                    .map(move |&file| PathBuf::new().join(path).join(file))
+            })
+            .collect::<Vec<PathBuf>>(),
+    );
+
+    for path in possible_paths {
+        let path_str = path.to_string_lossy().to_string();
+        if path.exists() {
+            return Ok(path_str);
+        }
+
+        tried_paths.push(path_str);
+    }
+
+    Err(tried_paths)
+}

src/plugins/kcp/config.rs

@@ -1,110 +0,0 @@
-use std::{io::Write, time::Duration};
-
-use kcp::Kcp;
-
-/// Kcp Delay Config
-#[derive(Debug, Clone, Copy)]
-pub struct KcpNoDelayConfig {
-    /// Enable nodelay
-    pub nodelay: bool,
-    /// Internal update interval (ms)
-    pub interval: i32,
-    /// ACK number to enable fast resend
-    pub resend: i32,
-    /// Disable congetion control
-    pub nc: bool,
-}
-
-impl Default for KcpNoDelayConfig {
-    fn default() -> KcpNoDelayConfig {
-        KcpNoDelayConfig {
-            nodelay: false,
-            interval: 100,
-            resend: 0,
-            nc: false,
-        }
-    }
-}
-
-#[allow(unused)]
-impl KcpNoDelayConfig {
-    /// Get a fastest configuration
-    ///
-    /// 1. Enable NoDelay
-    /// 2. Set ticking interval to be 10ms
-    /// 3. Set fast resend to be 2
-    /// 4. Disable congestion control
-    pub fn fastest() -> KcpNoDelayConfig {
-        KcpNoDelayConfig {
-            nodelay: true,
-            interval: 10,
-            resend: 2,
-            nc: true,
-        }
-    }
-
-    /// Get a normal configuration
-    ///
-    /// 1. Disable NoDelay
-    /// 2. Set ticking interval to be 40ms
-    /// 3. Disable fast resend
-    /// 4. Enable congestion control
-    pub fn normal() -> KcpNoDelayConfig {
-        KcpNoDelayConfig {
-            nodelay: false,
-            interval: 40,
-            resend: 0,
-            nc: false,
-        }
-    }
-}
-
-/// Kcp Config
-#[derive(Debug, Clone, Copy)]
-pub struct KcpConfig {
-    /// Max Transmission Unit
-    pub mtu: usize,
-    /// nodelay
-    pub nodelay: KcpNoDelayConfig,
-    /// Send window size
-    pub wnd_size: (u16, u16),
-    /// Session expire duration, default is 90 seconds
-    pub session_expire: Duration,
-    /// Flush KCP state immediately after write
-    pub flush_write: bool,
-    /// Flush ACKs immediately after input
-    pub flush_acks_input: bool,
-    /// Stream mode
-    pub stream: bool,
-}
-
-impl Default for KcpConfig {
-    fn default() -> KcpConfig {
-        KcpConfig {
-            mtu: 1400,
-            nodelay: KcpNoDelayConfig::normal(),
-            wnd_size: (256, 256),
-            session_expire: Duration::from_secs(90),
-            flush_write: false,
-            flush_acks_input: false,
-            stream: true,
-        }
-    }
-}
-
-impl KcpConfig {
-    /// Applies config onto `Kcp`
-    #[doc(hidden)]
-    pub fn apply_config<W: Write>(&self, k: &mut Kcp<W>) {
-        k.set_mtu(self.mtu).expect("invalid MTU");
-
-        k.set_nodelay(
-            self.nodelay.nodelay,
-            self.nodelay.interval,
-            self.nodelay.resend,
-            self.nodelay.nc,
-        );
-
-        k.set_wndsize(self.wnd_size.0, self.wnd_size.1);
-    }
-}

src/plugins/kcp/listener.rs

@@ -1,128 +0,0 @@
-use std::{
-    io::{self, ErrorKind},
-    net::SocketAddr,
-    sync::Arc,
-    time::Duration,
-};
-
-use byte_string::ByteStr;
-use kcp::{Error as KcpError, KcpResult};
-use log::{debug, error, trace};
-use tokio::{
-    net::{ToSocketAddrs, UdpSocket},
-    sync::mpsc,
-    task::JoinHandle,
-    time,
-};
-
-use crate::plugins::kcp::{config::KcpConfig, session::KcpSessionManager, stream::KcpStream};
-
-#[allow(unused)]
-pub struct KcpListener {
-    udp: Arc<UdpSocket>,
-    accept_rx: mpsc::Receiver<(KcpStream, SocketAddr)>,
-    task_watcher: JoinHandle<()>,
-}
-
-impl Drop for KcpListener {
-    fn drop(&mut self) {
-        self.task_watcher.abort();
-    }
-}
-
-impl KcpListener {
-    pub async fn bind<A: ToSocketAddrs>(config: KcpConfig, addr: A) -> KcpResult<KcpListener> {
-        let udp = UdpSocket::bind(addr).await?;
-        let udp = Arc::new(udp);
-        let server_udp = udp.clone();
-
-        let (accept_tx, accept_rx) = mpsc::channel(1024 /* backlogs */);
-        let task_watcher = tokio::spawn(async move {
-            let (close_tx, mut close_rx) = mpsc::channel(64);
-
-            let mut sessions = KcpSessionManager::new();
-            let mut packet_buffer = [0u8; 65536];
-            loop {
-                tokio::select! {
-                    conv = close_rx.recv() => {
-                        let conv = conv.expect("close_tx closed unexpectly");
-                        sessions.close_conv(conv);
-                        trace!("session conv: {} removed", conv);
-                    }
-
-                    recv_res = udp.recv_from(&mut packet_buffer) => {
-                        match recv_res {
-                            Err(err) => {
-                                error!("udp.recv_from failed, error: {}", err);
-                                time::sleep(Duration::from_secs(1)).await;
-                            }
-                            Ok((n, peer_addr)) => {
-                                let packet = &mut packet_buffer[..n];
-
-                                log::trace!("received peer: {}, {:?}", peer_addr, ByteStr::new(packet));
-
-                                let mut conv = kcp::get_conv(packet);
-                                if conv == 0 {
-                                    // Allocate a conv for client.
-                                    conv = sessions.alloc_conv();
-                                    debug!("allocate {} conv for peer: {}", conv, peer_addr);
-
-                                    kcp::set_conv(packet, conv);
-                                }
-
-                                let session = match sessions.get_or_create(&config, conv, &udp, peer_addr, &close_tx) {
-                                    Ok((s, created)) => {
-                                        if created {
-                                            // Created a new session, constructed a new accepted client
-                                            let stream = KcpStream::with_session(s.clone());
-                                            if let Err(..) = accept_tx.try_send((stream, peer_addr)) {
-                                                debug!("failed to create accepted stream due to channel failure");
-
-                                                // remove it from session
-                                                sessions.close_conv(conv);
-                                                continue;
-                                            }
-                                        }
-
-                                        s
-                                    },
-                                    Err(err) => {
-                                        error!("failed to create session, error: {}, peer: {}, conv: {}", err, peer_addr, conv);
-                                        continue;
-                                    }
-                                };
-
-                                // let mut kcp = session.kcp_socket().lock().await;
-                                // if let Err(err) = kcp.input(packet) {
-                                //     error!("kcp.input failed, peer: {}, conv: {}, error: {}, packet: {:?}", peer_addr, conv, err, ByteStr::new(packet));
-                                // }
-                                session.input(packet).await;
-                            }
-                        }
-                    }
-                }
-            }
-        });
-
-        Ok(KcpListener {
-            udp: server_udp,
-            accept_rx,
-            task_watcher,
-        })
-    }
-
-    pub async fn accept(&mut self) -> KcpResult<(KcpStream, SocketAddr)> {
-        match self.accept_rx.recv().await {
-            Some(s) => Ok(s),
-            None => Err(KcpError::IoError(io::Error::new(
-                ErrorKind::Other,
-                "accept channel closed unexpectly",
-            ))),
-        }
-    }
-
-    #[allow(unused)]
-    pub fn local_addr(&self) -> io::Result<SocketAddr> {
-        self.udp.local_addr()
-    }
-}

src/plugins/kcp/mod.rs

@@ -1,14 +0,0 @@
-//! Library of KCP on Tokio
-
-pub use self::{
-    config::{KcpConfig, KcpNoDelayConfig},
-    listener::KcpListener,
-    stream::KcpStream,
-};
-
-mod config;
-mod listener;
-mod session;
-mod skcp;
-mod stream;
-mod utils;

src/plugins/kcp/session.rs

@@ -1,256 +0,0 @@
-use std::{
-    collections::{hash_map::Entry, HashMap},
-    net::SocketAddr,
-    sync::{
-        atomic::{AtomicBool, Ordering},
-        Arc,
-    },
-    time::Duration,
-};
-
-use byte_string::ByteStr;
-use kcp::KcpResult;
-use log::{error, trace};
-use tokio::{
-    net::UdpSocket,
-    sync::{mpsc, Mutex},
-    time::{self, Instant},
-};
-
-use crate::plugins::kcp::{skcp::KcpSocket, KcpConfig};
-
-pub struct KcpSession {
-    socket: Mutex<KcpSocket>,
-    closed: AtomicBool,
-    session_expire: Duration,
-    session_close_notifier: Option<mpsc::Sender<u32>>,
-    input_tx: mpsc::Sender<Vec<u8>>,
-}
-
-impl KcpSession {
-    fn new(
-        socket: KcpSocket,
-        session_expire: Duration,
-        session_close_notifier: Option<mpsc::Sender<u32>>,
-        input_tx: mpsc::Sender<Vec<u8>>,
-    ) -> KcpSession {
-        KcpSession {
-            socket: Mutex::new(socket),
-            closed: AtomicBool::new(false),
-            session_expire,
-            session_close_notifier,
-            input_tx,
-        }
-    }
-
-    pub fn new_shared(
-        socket: KcpSocket,
-        session_expire: Duration,
-        session_close_notifier: Option<mpsc::Sender<u32>>,
-    ) -> Arc<KcpSession> {
-        let is_client = session_close_notifier.is_none();
-
-        let (input_tx, mut input_rx) = mpsc::channel(64);
-
-        let udp_socket = socket.udp_socket().clone();
-
-        let session = Arc::new(KcpSession::new(
-            socket,
-            session_expire,
-            session_close_notifier,
-            input_tx,
-        ));
-
-        {
-            let session = session.clone();
-            tokio::spawn(async move {
-                let mut input_buffer = [0u8; 65536];
-                let update_timer = time::sleep(Duration::from_millis(10));
-                tokio::pin!(update_timer);
-
-                loop {
-                    tokio::select! {
-                        // recv() then input()
-                        // Drives the KCP machine forward
-                        recv_result = udp_socket.recv(&mut input_buffer), if is_client => {
-                            match recv_result {
-                                Err(err) => {
-                                    error!("[SESSION] UDP recv failed, error: {}", err);
-                                }
-                                Ok(n) => {
-                                    let input_buffer = &input_buffer[..n];
-                                    trace!("[SESSION] UDP recv {} bytes, going to input {:?}", n, ByteStr::new(input_buffer));
-
-                                    let mut socket = session.socket.lock().await;
-
-                                    match socket.input(input_buffer) {
-                                        Ok(true) => {
-                                            trace!("[SESSION] UDP input {} bytes and waked sender/receiver", n);
-                                        }
-                                        Ok(false) => {}
-                                        Err(err) => {
-                                            error!("[SESSION] UDP input {} bytes error: {}, input buffer {:?}", n, err, ByteStr::new(input_buffer));
-                                        }
-                                    }
-                                }
-                            }
-                        }
-
-                        // bytes received from listener socket
-                        input_opt = input_rx.recv() => {
-                            if let Some(input_buffer) = input_opt {
-                                let mut socket = session.socket.lock().await;
-                                match socket.input(&input_buffer) {
-                                    Ok(..) => {
-                                        trace!("[SESSION] UDP input {} bytes from channel {:?}", input_buffer.len(), ByteStr::new(&input_buffer));
-                                    }
-                                    Err(err) => {
-                                        error!("[SESSION] UDP input {} bytes from channel failed, error: {}, input buffer {:?}",
-                                               input_buffer.len(), err, ByteStr::new(&input_buffer));
-                                    }
-                                }
-                            }
-                        }
-
-                        // Call update() in period
-                        _ = &mut update_timer => {
-                            let mut socket = session.socket.lock().await;
-
-                            let is_closed = session.closed.load(Ordering::Acquire);
-                            if is_closed && socket.can_close() {
-                                trace!("[SESSION] KCP session closed");
-                                break;
-                            }
-
-                            // server socket expires
-                            if !is_client {
-                                // If this is a server stream, close it automatically after a period of time
-                                let last_update_time = socket.last_update_time();
-                                let elapsed = last_update_time.elapsed();
-
-                                if elapsed > session.session_expire {
-                                    if elapsed > session.session_expire * 2 {
-                                        // Force close. Client may have already gone.
-                                        trace!(
-                                            "[SESSION] force close inactive session, conv: {}, last_update: {}s ago",
-                                            socket.conv(),
-                                            elapsed.as_secs()
-                                        );
-                                        break;
-                                    }
-
-                                    if !is_closed {
-                                        trace!(
-                                            "[SESSION] closing inactive session, conv: {}, last_update: {}s ago",
-                                            socket.conv(),
-                                            elapsed.as_secs()
-                                        );
-                                        session.closed.store(true, Ordering::Release);
-                                    }
-                                }
-                            }
-
-                            match socket.update() {
-                                Ok(next_next) => {
-                                    update_timer.as_mut().reset(Instant::from_std(next_next));
-                                }
-                                Err(err) => {
-                                    error!("[SESSION] KCP update failed, error: {}", err);
-                                    update_timer.as_mut().reset(Instant::now() + Duration::from_millis(10));
-                                }
-                            }
-                        }
-                    }
-                }
-
-                {
-                    // Close the socket.
-                    // Wake all pending tasks and let all send/recv return EOF
-
-                    let mut socket = session.socket.lock().await;
-                    socket.close();
-                }
-
-                if let Some(ref notifier) = session.session_close_notifier {
-                    let socket = session.socket.lock().await;
-                    let _ = notifier.send(socket.conv()).await;
-                }
-            });
-        }
-
-        session
-    }
-
-    pub fn kcp_socket(&self) -> &Mutex<KcpSocket> {
-        &self.socket
-    }
-
-    pub fn close(&self) {
-        self.closed.store(true, Ordering::Release);
-    }
-
-    pub async fn input(&self, buf: &[u8]) {
-        self.input_tx
-            .send(buf.to_owned())
-            .await
-            .expect("input channel closed")
-    }
-}
-
-pub struct KcpSessionManager {
-    sessions: HashMap<u32, Arc<KcpSession>>,
-    next_free_conv: u32,
-}
-
-impl KcpSessionManager {
-    pub fn new() -> KcpSessionManager {
-        KcpSessionManager {
-            sessions: HashMap::new(),
-            next_free_conv: 0,
-        }
-    }
-
-    pub fn close_conv(&mut self, conv: u32) {
-        self.sessions.remove(&conv);
-    }
-
-    pub fn alloc_conv(&mut self) -> u32 {
-        loop {
-            let (mut c, _) = self.next_free_conv.overflowing_add(1);
-            if c == 0 {
-                let (nc, _) = c.overflowing_add(1);
-                c = nc;
-            }
-            self.next_free_conv = c;
-
-            if self.sessions.get(&self.next_free_conv).is_none() {
-                let conv = self.next_free_conv;
-                return conv;
-            }
-        }
-    }
-
-    pub fn get_or_create(
-        &mut self,
-        config: &KcpConfig,
-        conv: u32,
-        udp: &Arc<UdpSocket>,
-        peer_addr: SocketAddr,
-        session_close_notifier: &mpsc::Sender<u32>,
-    ) -> KcpResult<(Arc<KcpSession>, bool)> {
-        match self.sessions.entry(conv) {
-            Entry::Occupied(occ) => Ok((occ.get().clone(), false)),
-            Entry::Vacant(vac) => {
-                let socket = KcpSocket::new(config, conv, udp.clone(), peer_addr, config.stream)?;
-                let session = KcpSession::new_shared(
-                    socket,
-                    config.session_expire,
-                    Some(session_close_notifier.clone()),
-                );
-                trace!("created session for conv: {}, peer: {}", conv, peer_addr);
-                vac.insert(session.clone());
-                Ok((session, true))
-            }
-        }
-    }
-}

src/plugins/kcp/skcp.rs

@@ -1,288 +0,0 @@
-use std::{
-    io::{self, ErrorKind, Write},
-    net::SocketAddr,
-    sync::Arc,
-    task::{Context, Poll, Waker},
-    time::{Duration, Instant},
-};
-
-use futures::future;
-use kcp::{Error as KcpError, Kcp, KcpResult};
-use log::{error, trace};
-use tokio::{net::UdpSocket, sync::mpsc};
-
-use crate::plugins::kcp::{utils::now_millis, KcpConfig};
-
-/// Writer for sending packets to the underlying UdpSocket
-struct UdpOutput {
-    socket: Arc<UdpSocket>,
-    target_addr: SocketAddr,
-    delay_tx: mpsc::UnboundedSender<Vec<u8>>,
-}
-
-impl UdpOutput {
-    /// Create a new Writer for writing packets to UdpSocket
-    pub fn new(socket: Arc<UdpSocket>, target_addr: SocketAddr) -> UdpOutput {
-        let (delay_tx, mut delay_rx) = mpsc::unbounded_channel::<Vec<u8>>();
-
-        {
-            let socket = socket.clone();
-            tokio::spawn(async move {
-                while let Some(buf) = delay_rx.recv().await {
-                    if let Err(err) = socket.send_to(&buf, target_addr).await {
-                        error!("[SEND] UDP delayed send failed, error: {}", err);
-                    }
-                }
-            });
-        }
-
-        UdpOutput {
-            socket,
-            target_addr,
-            delay_tx,
-        }
-    }
-}
-
-impl Write for UdpOutput {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        match self.socket.try_send_to(buf, self.target_addr) {
-            Ok(n) => Ok(n),
-            Err(ref err) if err.kind() == ErrorKind::WouldBlock => {
-                // send return EAGAIN
-                // ignored as packet was lost in transmission
-                trace!(
-                    "[SEND] UDP send EAGAIN, packet.size: {} bytes, delayed send",
-                    buf.len()
-                );
-
-                self.delay_tx
-                    .send(buf.to_owned())
-                    .expect("channel closed unexpectly");
-
-                Ok(buf.len())
-            }
-            Err(err) => Err(err),
-        }
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        Ok(())
-    }
-}
-
-pub struct KcpSocket {
-    kcp: Kcp<UdpOutput>,
-    last_update: Instant,
-    socket: Arc<UdpSocket>,
-    flush_write: bool,
-    flush_ack_input: bool,
-    sent_first: bool,
-    pending_sender: Option<Waker>,
-    pending_receiver: Option<Waker>,
-    closed: bool,
-}
-
-impl KcpSocket {
-    pub fn new(
-        c: &KcpConfig,
-        conv: u32,
-        socket: Arc<UdpSocket>,
-        target_addr: SocketAddr,
-        stream: bool,
-    ) -> KcpResult<KcpSocket> {
-        let output = UdpOutput::new(socket.clone(), target_addr);
-        let mut kcp = if stream {
-            Kcp::new_stream(conv, output)
-        } else {
-            Kcp::new(conv, output)
-        };
-        c.apply_config(&mut kcp);
-
-        // Ask server to allocate one
-        if conv == 0 {
-            kcp.input_conv();
-        }
-
-        kcp.update(now_millis())?;
-
-        Ok(KcpSocket {
-            kcp,
-            last_update: Instant::now(),
-            socket,
-            flush_write: c.flush_write,
-            flush_ack_input: c.flush_acks_input,
-            sent_first: false,
-            pending_sender: None,
-            pending_receiver: None,
-            closed: false,
-        })
-    }
-
-    /// Call every time you got data from transmission
-    pub fn input(&mut self, buf: &[u8]) -> KcpResult<bool> {
-        match self.kcp.input(buf) {
-            Ok(..) => {}
-            Err(KcpError::ConvInconsistent(expected, actual)) => {
-                trace!(
-                    "[INPUT] Conv expected={} actual={} ignored",
-                    expected,
-                    actual
-                );
-                return Ok(false);
-            }
-            Err(err) => return Err(err),
-        }
-        self.last_update = Instant::now();
-
-        if self.flush_ack_input {
-            self.kcp.flush_ack()?;
-        }
-
-        Ok(self.try_wake_pending_waker())
-    }
-
-    /// Call if you want to send some data
-    pub fn poll_send(&mut self, cx: &mut Context<'_>, mut buf: &[u8]) -> Poll<KcpResult<usize>> {
-        if self.closed {
-            return Ok(0).into();
-        }
-
-        // If:
-        //     1. Have sent the first packet (asking for conv)
-        //     2. Too many pending packets
-        if self.sent_first
-            && (self.kcp.wait_snd() >= self.kcp.snd_wnd() as usize || self.kcp.waiting_conv())
-        {
-            trace!(
-                "[SEND] waitsnd={} sndwnd={} excceeded or waiting conv={}",
-                self.kcp.wait_snd(),
-                self.kcp.snd_wnd(),
-                self.kcp.waiting_conv()
-            );
-            self.pending_sender = Some(cx.waker().clone());
-            return Poll::Pending;
-        }
-
-        if !self.sent_first && self.kcp.waiting_conv() && buf.len() > self.kcp.mss() as usize {
-            buf = &buf[..self.kcp.mss() as usize];
-        }
-
-        let n = self.kcp.send(buf)?;
-        self.sent_first = true;
-        self.last_update = Instant::now();
-
-        if self.flush_write {
-            self.kcp.flush()?;
-        }
-
-        Ok(n).into()
-    }
-
-    /// Call if you want to send some data
-    #[allow(dead_code)]
-    pub async fn send(&mut self, buf: &[u8]) -> KcpResult<usize> {
-        future::poll_fn(|cx| self.poll_send(cx, buf)).await
-    }
-
-    #[allow(dead_code)]
-    pub fn try_recv(&mut self, buf: &mut [u8]) -> KcpResult<usize> {
-        if self.closed {
-            return Ok(0);
-        }
-        self.kcp.recv(buf)
-    }
-
-    pub fn poll_recv(&mut self, cx: &mut Context<'_>, buf: &mut [u8]) -> Poll<KcpResult<usize>> {
-        if self.closed {
-            return Ok(0).into();
-        }
-
-        match self.kcp.recv(buf) {
-            Ok(n) => Ok(n).into(),
-            Err(KcpError::RecvQueueEmpty) => {
-                self.pending_receiver = Some(cx.waker().clone());
-                Poll::Pending
-            }
-            Err(err) => Err(err).into(),
-        }
-    }
-
-    #[allow(dead_code)]
-    pub async fn recv(&mut self, buf: &mut [u8]) -> KcpResult<usize> {
-        future::poll_fn(|cx| self.poll_recv(cx, buf)).await
-    }
-
-    pub fn flush(&mut self) -> KcpResult<()> {
-        self.kcp.flush()?;
-        self.last_update = Instant::now();
-        Ok(())
-    }
-
-    fn try_wake_pending_waker(&mut self) -> bool {
-        let mut waked = false;
-
-        if self.pending_sender.is_some()
-            && self.kcp.wait_snd() < self.kcp.snd_wnd() as usize
-            && !self.kcp.waiting_conv()
-        {
-            let waker = self.pending_sender.take().unwrap();
-            waker.wake();
-
-            waked = true;
-        }
-
-        if self.pending_receiver.is_some() {
-            if let Ok(peek) = self.kcp.peeksize() {
-                if peek > 0 {
-                    let waker = self.pending_receiver.take().unwrap();
-                    waker.wake();
-
-                    waked = true;
-                }
-            }
-        }
-
-        waked
-    }
-
-    pub fn update(&mut self) -> KcpResult<Instant> {
-        let now = now_millis();
-        self.kcp.update(now)?;
-        let next = self.kcp.check(now);
-
-        self.try_wake_pending_waker();
-
-        Ok(Instant::now() + Duration::from_millis(next as u64))
-    }
-
-    pub fn close(&mut self) {
-        self.closed = true;
-        if let Some(w) = self.pending_sender.take() {
-            w.wake();
-        }
-        if let Some(w) = self.pending_receiver.take() {
-            w.wake();
-        }
-    }
-
-    pub fn udp_socket(&self) -> &Arc<UdpSocket> {
-        &self.socket
-    }
-
-    pub fn can_close(&self) -> bool {
-        self.kcp.wait_snd() == 0
-    }
-
-    pub fn conv(&self) -> u32 {
-        self.kcp.conv()
-    }
-
-    pub fn peek_size(&self) -> KcpResult<usize> {
-        self.kcp.peeksize()
-    }
-
-    pub fn last_update_time(&self) -> Instant {
-        self.last_update
-    }
-}

src/plugins/kcp/stream.rs

@@ -1,183 +0,0 @@
-use std::{
-    io::{self, ErrorKind},
-    net::{IpAddr, SocketAddr},
-    pin::Pin,
-    sync::Arc,
-    task::{Context, Poll},
-};
-
-use futures::{future, ready};
-use kcp::{Error as KcpError, KcpResult};
-use log::trace;
-use tokio::{
-    io::{AsyncRead, AsyncWrite, ReadBuf},
-    net::UdpSocket,
-};
-
-use crate::plugins::kcp::{config::KcpConfig, session::KcpSession, skcp::KcpSocket};
-
-pub struct KcpStream {
-    session: Arc<KcpSession>,
-    recv_buffer: Vec<u8>,
-    recv_buffer_pos: usize,
-    recv_buffer_cap: usize,
-}
-
-impl Drop for KcpStream {
-    fn drop(&mut self) {
-        self.session.close();
-    }
-}
-
-#[allow(unused)]
-impl KcpStream {
-    pub async fn connect(config: &KcpConfig, addr: SocketAddr) -> KcpResult<KcpStream> {
-        let udp = match addr.ip() {
-            IpAddr::V4(..) => UdpSocket::bind("0.0.0.0:0").await?,
-            IpAddr::V6(..) => UdpSocket::bind("[::]:0").await?,
-        };
-
-        let udp = Arc::new(udp);
-        let socket = KcpSocket::new(config, 0, udp, addr, config.stream)?;
-
-        let session = KcpSession::new_shared(socket, config.session_expire, None);
-
-        Ok(KcpStream::with_session(session))
-    }
-
-    pub(crate) fn with_session(session: Arc<KcpSession>) -> KcpStream {
-        KcpStream {
-            session,
-            recv_buffer: Vec::new(),
-            recv_buffer_pos: 0,
-            recv_buffer_cap: 0,
-        }
-    }
-
-    pub fn poll_send(&mut self, cx: &mut Context<'_>, buf: &[u8]) -> Poll<KcpResult<usize>> {
-        // Mutex doesn't have poll_lock, spinning on it.
-        let socket = self.session.kcp_socket();
-        let mut kcp = match socket.try_lock() {
-            Ok(guard) => guard,
-            Err(..) => {
-                cx.waker().wake_by_ref();
-                return Poll::Pending;
-            }
-        };
-
-        kcp.poll_send(cx, buf)
-    }
-
-    pub async fn send(&mut self, buf: &[u8]) -> KcpResult<usize> {
-        future::poll_fn(|cx| self.poll_send(cx, buf)).await
-    }
-
-    pub fn poll_recv(&mut self, cx: &mut Context<'_>, buf: &mut [u8]) -> Poll<KcpResult<usize>> {
-        loop {
-            // Consumes all data in buffer
-            if self.recv_buffer_pos < self.recv_buffer_cap {
-                let remaining = self.recv_buffer_cap - self.recv_buffer_pos;
-                let copy_length = remaining.min(buf.len());
-
-                buf.copy_from_slice(
-                    &self.recv_buffer[self.recv_buffer_pos..self.recv_buffer_pos + copy_length],
-                );
-                self.recv_buffer_pos += copy_length;
-                return Ok(copy_length).into();
-            }
-
-            // Mutex doesn't have poll_lock, spinning on it.
-            let socket = self.session.kcp_socket();
-            let mut kcp = match socket.try_lock() {
-                Ok(guard) => guard,
-                Err(..) => {
-                    cx.waker().wake_by_ref();
-                    return Poll::Pending;
-                }
-            };
-
-            // Try to read from KCP
-            // 1. Read directly with user provided `buf`
-            match ready!(kcp.poll_recv(cx, buf)) {
-                Ok(n) => {
-                    trace!("[CLIENT] recv directly {} bytes", n);
-                    return Ok(n).into();
-                }
-                Err(KcpError::UserBufTooSmall) => {}
-                Err(err) => return Err(err).into(),
-            }
-
-            // 2. User `buf` too small, read to recv_buffer
-            let required_size = kcp.peek_size()?;
-            if self.recv_buffer.len() < required_size {
-                self.recv_buffer.resize(required_size, 0);
-            }
-
-            match ready!(kcp.poll_recv(cx, &mut self.recv_buffer)) {
-                Ok(n) => {
-                    trace!("[CLIENT] recv buffered {} bytes", n);
-                    self.recv_buffer_pos = 0;
-                    self.recv_buffer_cap = n;
-                }
-                Err(err) => return Err(err).into(),
-            }
-        }
-    }
-
-    pub async fn recv(&mut self, buf: &mut [u8]) -> KcpResult<usize> {
-        future::poll_fn(|cx| self.poll_recv(cx, buf)).await
-    }
-}
-
-impl AsyncRead for KcpStream {
-    fn poll_read(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-        buf: &mut ReadBuf<'_>,
-    ) -> Poll<io::Result<()>> {
-        match ready!(self.poll_recv(cx, buf.initialize_unfilled())) {
-            Ok(n) => {
-                buf.advance(n);
-                Ok(()).into()
-            }
-            Err(KcpError::IoError(err)) => Err(err).into(),
-            Err(err) => Err(io::Error::new(ErrorKind::Other, err)).into(),
-        }
-    }
-}
-
-impl AsyncWrite for KcpStream {
-    fn poll_write(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context<'_>,
-        buf: &[u8],
-    ) -> Poll<io::Result<usize>> {
-        match ready!(self.poll_send(cx, buf)) {
-            Ok(n) => Ok(n).into(),
-            Err(KcpError::IoError(err)) => Err(err).into(),
-            Err(err) => Err(io::Error::new(ErrorKind::Other, err)).into(),
-        }
-    }
-
-    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-        // Mutex doesn't have poll_lock, spinning on it.
-        let socket = self.session.kcp_socket();
-        let mut kcp = match socket.try_lock() {
-            Ok(guard) => guard,
-            Err(..) => {
-                cx.waker().wake_by_ref();
-                return Poll::Pending;
-            }
-        };
-
-        match kcp.flush() {
-            Ok(..) => Ok(()).into(),
-            Err(KcpError::IoError(err)) => Err(err).into(),
-            Err(err) => Err(io::Error::new(ErrorKind::Other, err)).into(),
-        }
-    }
-
-    fn poll_shutdown(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-        Ok(()).into()
-    }
-}

src/plugins/kcp/utils.rs

@@ -1,10 +0,0 @@
-use std::time::{SystemTime, UNIX_EPOCH};
-
-#[inline]
-pub fn now_millis() -> u32 {
-    let start = SystemTime::now();
-    let since_the_epoch = start
-        .duration_since(UNIX_EPOCH)
-        .expect("time went afterwards");
-    (since_the_epoch.as_secs() * 1000 + since_the_epoch.subsec_millis() as u64 / 1_000_000) as u32
-}

src/plugins/mod.rs

@@ -1 +0,0 @@
-pub mod kcp;

src/servers/mod.rs

@@ -2,34 +2,36 @@ use log::{error, info};
 use std::collections::{HashMap, HashSet};
 use std::net::SocketAddr;
 use std::sync::Arc;
+
 use tokio::task::JoinHandle;
 
 mod protocol;
-use crate::config::{ParsedConfig, Upstream};
+pub(crate) mod upstream_address;
-use protocol::{kcp, tcp};
+
+use crate::config::ParsedConfigV1;
+use crate::upstreams::Upstream;
+use protocol::tcp;
 
 #[derive(Debug)]
-pub struct Server {
+pub(crate) struct Server {
     pub proxies: Vec<Arc<Proxy>>,
-    pub config: ParsedConfig,
 }
 
 #[derive(Debug, Clone)]
-pub struct Proxy {
+pub(crate) struct Proxy {
     pub name: String,
     pub listen: SocketAddr,
     pub protocol: String,
     pub tls: bool,
     pub sni: Option<HashMap<String, String>>,
-    pub default: String,
+    pub default_action: String,
     pub upstream: HashMap<String, Upstream>,
 }
 
 impl Server {
-    pub fn new(config: ParsedConfig) -> Self {
+    pub fn new_from_v1_config(config: ParsedConfigV1) -> Self {
         let mut new_server = Server {
             proxies: Vec::new(),
-            config: config.clone(),
         };
 
         for (name, proxy) in config.servers.iter() {
@@ -60,7 +62,7 @@ impl Server {
                     protocol: protocol.clone(),
                     tls,
                     sni: sni.clone(),
-                    default: default.clone(),
+                    default_action: default.clone(),
                     upstream: upstream.clone(),
                 };
                 new_server.proxies.push(Arc::new(proxy));
@@ -82,18 +84,12 @@ impl Server {
             );
             let handle = tokio::spawn(async move {
                 match config.protocol.as_ref() {
-                    "tcp" => {
+                    "tcp" | "tcp4" | "tcp6" => {
                         let res = tcp::proxy(config.clone()).await;
                         if res.is_err() {
                             error!("Failed to start {}: {}", config.name, res.err().unwrap());
                         }
                     }
-                    "kcp" => {
-                        let res = kcp::proxy(config.clone()).await;
-                        if res.is_err() {
-                            error!("Failed to start {}: {}", config.name, res.err().unwrap());
-                        }
-                    }
                     _ => {
                         error!("Invalid protocol: {}", config.protocol)
                     }
@@ -111,12 +107,10 @@ impl Server {
 
 #[cfg(test)]
 mod tests {
-    use crate::plugins::kcp::{KcpConfig, KcpStream};
-    use std::net::SocketAddr;
     use std::thread::{self, sleep};
     use std::time::Duration;
     use tokio::io::{AsyncReadExt, AsyncWriteExt};
-    use tokio::net::{TcpListener, TcpStream};
+    use tokio::net::TcpListener;
 
     use super::*;
 
@@ -129,7 +123,7 @@ mod tests {
             let mut buf = [0u8; 2];
             let mut n = stream.read(&mut buf).await.unwrap();
             while n > 0 {
-                stream.write(b"hello").await.unwrap();
+                let _ = stream.write(b"hello").await.unwrap();
                 if buf.eq(b"by") {
                     stream.shutdown().await.unwrap();
                     break;
@@ -142,9 +136,9 @@ mod tests {
 
     #[tokio::test]
     async fn test_proxy() {
-        use crate::config::Config;
+        use crate::config::ConfigV1;
-        let config = Config::new("tests/config.yaml").unwrap();
+        let config = ConfigV1::new("tests/config.yaml").unwrap();
-        let mut server = Server::new(config.base);
+        let mut server = Server::new_from_v1_config(config.base);
         thread::spawn(move || {
             tcp_mock_server();
         });
@@ -155,43 +149,25 @@ mod tests {
         sleep(Duration::from_secs(1)); // wait for server to start
 
         // test TCP proxy
-        let mut conn = TcpStream::connect("127.0.0.1:54500").await.unwrap();
+        let mut conn = tokio::net::TcpStream::connect("127.0.0.1:54500")
+            .await
+            .unwrap();
         let mut buf = [0u8; 5];
-        conn.write(b"hi").await.unwrap();
+        let _ = conn.write(b"hi").await.unwrap();
-        conn.read(&mut buf).await.unwrap();
+        let _ = conn.read(&mut buf).await.unwrap();
         assert_eq!(&buf, b"hello");
         conn.shutdown().await.unwrap();
 
         // test TCP echo
-        let mut conn = TcpStream::connect("127.0.0.1:54956").await.unwrap();
+        let mut conn = tokio::net::TcpStream::connect("127.0.0.1:54956")
+            .await
+            .unwrap();
         let mut buf = [0u8; 1];
         for i in 0..=10u8 {
-            conn.write(&[i]).await.unwrap();
+            let _ = conn.write(&[i]).await.unwrap();
-            conn.read(&mut buf).await.unwrap();
+            let _ = conn.read(&mut buf).await.unwrap();
             assert_eq!(&buf, &[i]);
         }
         conn.shutdown().await.unwrap();
-
-        // test KCP echo
-        let kcp_config = KcpConfig::default();
-        let server_addr: SocketAddr = "127.0.0.1:54959".parse().unwrap();
-        let mut conn = KcpStream::connect(&kcp_config, server_addr).await.unwrap();
-        let mut buf = [0u8; 1];
-        for i in 0..=10u8 {
-            conn.write(&[i]).await.unwrap();
-            conn.read(&mut buf).await.unwrap();
-            assert_eq!(&buf, &[i]);
-        }
-        conn.shutdown().await.unwrap();
-
-        // test KCP proxy and close mock server
-        let kcp_config = KcpConfig::default();
-        let server_addr: SocketAddr = "127.0.0.1:54958".parse().unwrap();
-        let mut conn = KcpStream::connect(&kcp_config, server_addr).await.unwrap();
-        let mut buf = [0u8; 5];
-        conn.write(b"by").await.unwrap();
-        conn.read(&mut buf).await.unwrap();
-        assert_eq!(&buf, b"hello");
-        conn.shutdown().await.unwrap();
     }
 }

src/servers/protocol/kcp.rs

@@ -1,112 +0,0 @@
-use crate::config::Upstream;
-use crate::plugins::kcp::{KcpConfig, KcpListener, KcpStream};
-use crate::servers::Proxy;
-use futures::future::try_join;
-use log::{debug, error, warn};
-use std::net::SocketAddr;
-use std::sync::Arc;
-use tokio::io;
-use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
-use tokio::net::TcpStream;
-
-pub async fn proxy(config: Arc<Proxy>) -> Result<(), Box<dyn std::error::Error>> {
-    let kcp_config = KcpConfig::default();
-    let mut listener = KcpListener::bind(kcp_config, config.listen).await?;
-    let config = config.clone();
-
-    loop {
-        let thread_proxy = config.clone();
-        match listener.accept().await {
-            Err(err) => {
-                error!("Failed to accept connection: {}", err);
-                return Err(Box::new(err));
-            }
-            Ok((stream, peer)) => {
-                tokio::spawn(async move {
-                    match accept(stream, peer, thread_proxy).await {
-                        Ok(_) => {}
-                        Err(err) => {
-                            error!("Relay thread returned an error: {}", err);
-                        }
-                    };
-                });
-            }
-        }
-    }
-}
-
-async fn accept(
-    inbound: KcpStream,
-    peer: SocketAddr,
-    proxy: Arc<Proxy>,
-) -> Result<(), Box<dyn std::error::Error>> {
-    debug!("New connection from {:?}", peer);
-
-    let upstream_name = proxy.default.clone();
-
-    debug!("Upstream: {}", upstream_name);
-
-    let upstream = match proxy.upstream.get(&upstream_name) {
-        Some(upstream) => upstream,
-        None => {
-            warn!(
-                "No upstream named {:?} on server {:?}",
-                proxy.default, proxy.name
-            );
-            return process(inbound, proxy.upstream.get(&proxy.default).unwrap()).await;
-            // ToDo: Remove unwrap and check default option
-        }
-    };
-    return process(inbound, upstream).await;
-}
-
-async fn process(
-    mut inbound: KcpStream,
-    upstream: &Upstream,
-) -> Result<(), Box<dyn std::error::Error>> {
-    match upstream {
-        Upstream::Ban => {
-            let _ = inbound.shutdown();
-        }
-        Upstream::Echo => {
-            let (mut ri, mut wi) = io::split(inbound);
-            let inbound_to_inbound = copy(&mut ri, &mut wi);
-            let bytes_tx = inbound_to_inbound.await;
-            debug!("Bytes read: {:?}", bytes_tx);
-        }
-        Upstream::Custom(custom) => match custom.protocol.as_ref() {
-            "tcp" => {
-                let outbound = TcpStream::connect(custom.addr.clone()).await?;
-
-                let (mut ri, mut wi) = io::split(inbound);
-                let (mut ro, mut wo) = io::split(outbound);
-
-                let inbound_to_outbound = copy(&mut ri, &mut wo);
-                let outbound_to_inbound = copy(&mut ro, &mut wi);
-
-                let (bytes_tx, bytes_rx) =
-                    try_join(inbound_to_outbound, outbound_to_inbound).await?;
-
-                debug!("Bytes read: {:?} write: {:?}", bytes_tx, bytes_rx);
-            }
-            _ => {
-                error!("Reached unknown protocol: {:?}", custom.protocol);
-            }
-        },
-    };
-    Ok(())
-}
-
-async fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> io::Result<u64>
-where
-    R: AsyncRead + Unpin + ?Sized,
-    W: AsyncWrite + Unpin + ?Sized,
-{
-    match io::copy(reader, writer).await {
-        Ok(u64) => {
-            let _ = writer.shutdown().await;
-            Ok(u64)
-        }
-        Err(_) => Ok(0),
-    }
-}

src/servers/protocol/mod.rs

@@ -1,3 +1,2 @@
-pub mod kcp;
 pub mod tcp;
 pub mod tls;

src/servers/protocol/tcp.rs

@@ -1,14 +1,11 @@
-use crate::config::Upstream;
 use crate::servers::protocol::tls::get_sni;
 use crate::servers::Proxy;
-use futures::future::try_join;
+use log::{debug, error, info, warn};
-use log::{debug, error, warn};
+use std::error::Error;
 use std::sync::Arc;
-use tokio::io;
-use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};
 
-pub async fn proxy(config: Arc<Proxy>) -> Result<(), Box<dyn std::error::Error>> {
+pub(crate) async fn proxy(config: Arc<Proxy>) -> Result<(), Box<dyn Error>> {
     let listener = TcpListener::bind(config.listen).await?;
     let config = config.clone();
 
@@ -33,21 +30,21 @@ pub async fn proxy(config: Arc<Proxy>) -> Result<(), Box<dyn std::error::Error>>
     }
 }
 
-async fn accept(inbound: TcpStream, proxy: Arc<Proxy>) -> Result<(), Box<dyn std::error::Error>> {
+async fn accept(inbound: TcpStream, proxy: Arc<Proxy>) -> Result<(), Box<dyn Error>> {
-    debug!("New connection from {:?}", inbound.peer_addr()?);
+    info!("New connection from {:?}", inbound.peer_addr()?);
 
     let upstream_name = match proxy.tls {
-        false => proxy.default.clone(),
+        false => proxy.default_action.clone(),
         true => {
             let mut hello_buf = [0u8; 1024];
             inbound.peek(&mut hello_buf).await?;
             let snis = get_sni(&hello_buf);
             if snis.is_empty() {
-                proxy.default.clone()
+                proxy.default_action.clone()
             } else {
                 match proxy.sni.clone() {
                     Some(sni_map) => {
-                        let mut upstream = proxy.default.clone();
+                        let mut upstream = proxy.default_action.clone();
                         for sni in snis {
                             let m = sni_map.get(&sni);
                             if m.is_some() {
@@ -57,7 +54,7 @@ async fn accept(inbound: TcpStream, proxy: Arc<Proxy>) -> Result<(), Box<dyn std
                         }
                         upstream
                     }
-                    None => proxy.default.clone(),
+                    None => proxy.default_action.clone(),
                 }
             }
         }
@@ -70,62 +67,11 @@ async fn accept(inbound: TcpStream, proxy: Arc<Proxy>) -> Result<(), Box<dyn std
         None => {
             warn!(
                 "No upstream named {:?} on server {:?}",
-                proxy.default, proxy.name
+                proxy.default_action, proxy.name
             );
-            return process(inbound, proxy.upstream.get(&proxy.default).unwrap()).await;
+            proxy.upstream.get(&proxy.default_action).unwrap()
-            // ToDo: Remove unwrap and check default option
         }
     };
-    return process(inbound, upstream).await;
-}
 
-async fn process(
+    upstream.process(inbound).await
-    mut inbound: TcpStream,
-    upstream: &Upstream,
-) -> Result<(), Box<dyn std::error::Error>> {
-    match upstream {
-        Upstream::Ban => {
-            let _ = inbound.shutdown();
-        }
-        Upstream::Echo => {
-            let (mut ri, mut wi) = io::split(inbound);
-            let inbound_to_inbound = copy(&mut ri, &mut wi);
-            let bytes_tx = inbound_to_inbound.await;
-            debug!("Bytes read: {:?}", bytes_tx);
-        }
-        Upstream::Custom(custom) => match custom.protocol.as_ref() {
-            "tcp" => {
-                let outbound = TcpStream::connect(custom.addr.clone()).await?;
-
-                let (mut ri, mut wi) = io::split(inbound);
-                let (mut ro, mut wo) = io::split(outbound);
-
-                let inbound_to_outbound = copy(&mut ri, &mut wo);
-                let outbound_to_inbound = copy(&mut ro, &mut wi);
-
-                let (bytes_tx, bytes_rx) =
-                    try_join(inbound_to_outbound, outbound_to_inbound).await?;
-
-                debug!("Bytes read: {:?} write: {:?}", bytes_tx, bytes_rx);
-            }
-            _ => {
-                error!("Reached unknown protocol: {:?}", custom.protocol);
-            }
-        },
-    };
-    Ok(())
-}
-
-async fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> io::Result<u64>
-where
-    R: AsyncRead + Unpin + ?Sized,
-    W: AsyncWrite + Unpin + ?Sized,
-{
-    match io::copy(reader, writer).await {
-        Ok(u64) => {
-            let _ = writer.shutdown().await;
-            Ok(u64)
-        }
-        Err(_) => Ok(0),
-    }
 }

src/servers/protocol/tls.rs

@@ -49,6 +49,7 @@ pub fn get_sni(buf: &[u8]) -> Vec<String> {
         }
     }
 
+    debug!("Found SNIs: {:?}", &snis);
     snis
 }
 
@@ -98,6 +99,6 @@ mod tests {
             0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
         ];
         let sni = get_sni(&BUF);
-        assert!(sni[0] == "www.lirui.tech".to_string());
+        assert!(sni[0] == *"www.lirui.tech");
     }
 }

src/servers/upstream_address.rs

@@ -0,0 +1,147 @@
+use log::debug;
+use std::fmt::{Display, Formatter};
+use std::io::Result;
+use std::net::SocketAddr;
+use std::sync::Arc;
+use std::sync::RwLock;
+use time::{Duration, Instant, OffsetDateTime};
+
+#[derive(Debug, Clone, Default)]
+pub(crate) struct UpstreamAddress {
+    address: String,
+    resolved_addresses: Arc<RwLock<Vec<SocketAddr>>>,
+    resolved_time: Arc<RwLock<Option<Instant>>>,
+    ttl: Arc<RwLock<Option<Duration>>>,
+}
+
+impl Display for UpstreamAddress {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        self.address.fmt(f)
+    }
+}
+
+impl UpstreamAddress {
+    pub fn new(address: String) -> Self {
+        UpstreamAddress {
+            address,
+            ..Default::default()
+        }
+    }
+
+    pub fn is_valid(&self) -> bool {
+        let r = { *self.resolved_time.read().unwrap() };
+
+        if let Some(resolved) = r {
+            if let Some(ttl) = { *self.ttl.read().unwrap() } {
+                return resolved.elapsed() < ttl;
+            }
+        }
+
+        false
+    }
+
+    fn is_resolved(&self) -> bool {
+        !self.resolved_addresses.read().unwrap().is_empty()
+    }
+
+    fn time_remaining(&self) -> Duration {
+        if !self.is_valid() {
+            return Duration::seconds(0);
+        }
+
+        let rt = { *self.resolved_time.read().unwrap() };
+        let ttl = { *self.ttl.read().unwrap() };
+        ttl.unwrap() - rt.unwrap().elapsed()
+    }
+
+    pub async fn resolve(&self, mode: ResolutionMode) -> Result<Vec<SocketAddr>> {
+        if self.is_resolved() && self.is_valid() {
+            debug!(
+                "Already got address {:?}, still valid for {:.3}s",
+                &self.resolved_addresses,
+                self.time_remaining().as_seconds_f64()
+            );
+            return Ok(self.resolved_addresses.read().unwrap().clone());
+        }
+
+        debug!(
+            "Resolving addresses for {} with mode {:?}",
+            &self.address, &mode
+        );
+
+        let lookup_result = tokio::net::lookup_host(&self.address).await;
+
+        let resolved_addresses: Vec<SocketAddr> = match lookup_result {
+            Ok(resolved_addresses) => resolved_addresses.into_iter().collect(),
+            Err(e) => {
+                debug!("Failed looking up {}: {}", &self.address, &e);
+                // Protect against DNS flooding. Cache the result for 1 second.
+                *self.resolved_time.write().unwrap() = Some(Instant::now());
+                *self.ttl.write().unwrap() = Some(Duration::seconds(3));
+                return Err(e);
+            }
+        };
+
+        debug!("Resolved addresses: {:?}", &resolved_addresses);
+
+        let addresses: Vec<SocketAddr> = match mode {
+            ResolutionMode::Ipv4 => resolved_addresses
+                .into_iter()
+                .filter(|a| a.is_ipv4())
+                .collect(),
+
+            ResolutionMode::Ipv6 => resolved_addresses
+                .into_iter()
+                .filter(|a| a.is_ipv6())
+                .collect(),
+
+            _ => resolved_addresses,
+        };
+
+        debug!(
+            "Got {} addresses for {}: {:?}",
+            &mode, &self.address, &addresses
+        );
+        debug!(
+            "Resolved at {}",
+            OffsetDateTime::now_utc()
+                .format(&time::format_description::well_known::Rfc3339)
+                .expect("Format")
+        );
+
+        *self.resolved_addresses.write().unwrap() = addresses.clone();
+        *self.resolved_time.write().unwrap() = Some(Instant::now());
+        *self.ttl.write().unwrap() = Some(Duration::minutes(1));
+
+        Ok(addresses)
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+pub(crate) enum ResolutionMode {
+    #[default]
+    Ipv4AndIpv6,
+    Ipv4,
+    Ipv6,
+}
+
+impl From<&str> for ResolutionMode {
+    fn from(value: &str) -> Self {
+        match value {
+            "tcp4" => ResolutionMode::Ipv4,
+            "tcp6" => ResolutionMode::Ipv6,
+            "tcp" => ResolutionMode::Ipv4AndIpv6,
+            _ => panic!("This should never happen. Please check configuration parser."),
+        }
+    }
+}
+
+impl Display for ResolutionMode {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ResolutionMode::Ipv4 => write!(f, "IPv4Only"),
+            ResolutionMode::Ipv6 => write!(f, "IPv6Only"),
+            ResolutionMode::Ipv4AndIpv6 => write!(f, "IPv4 and IPv6"),
+        }
+    }
+}

src/update.rs

@@ -0,0 +1,22 @@
+use self_update::{cargo_crate_version, version};
+
+pub(crate) fn update() {
+    println!("Updating to the latest version...");
+
+    let backend = self_update::backends::gitea::Update::configure()
+        .with_host("https://code.kiers.eu")
+        .repo_owner("jjkiers")
+        .repo_name("layer4-proxy")
+        .bin_name("l4p")
+        .show_download_progress(true)
+        .current_version(cargo_crate_version!())
+        .build()
+        .expect("Should initialize correctly.");
+
+    let status = backend.update_extended();
+
+    match status {
+        Err(e) => eprintln!("Error updating: {e}"),
+        Ok(_) => (),
+    }
+}

src/upstreams/mod.rs

@@ -0,0 +1,51 @@
+mod proxy_to_upstream;
+
+use log::debug;
+use serde::Deserialize;
+use std::error::Error;
+use tokio::io;
+use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
+use tokio::net::TcpStream;
+
+pub use crate::upstreams::proxy_to_upstream::ProxyToUpstream;
+
+#[derive(Debug, Clone, Deserialize)]
+pub enum Upstream {
+    Ban,
+    Echo,
+    Proxy(ProxyToUpstream),
+}
+
+impl Upstream {
+    pub(crate) async fn process(&self, mut inbound: TcpStream) -> Result<(), Box<dyn Error>> {
+        match self {
+            Upstream::Ban => {
+                inbound.shutdown().await?;
+            }
+            Upstream::Echo => {
+                let (mut ri, mut wi) = io::split(inbound);
+                let inbound_to_inbound = copy(&mut ri, &mut wi);
+                let bytes_tx = inbound_to_inbound.await;
+                debug!("Bytes read: {:?}", bytes_tx);
+            }
+            Upstream::Proxy(config) => {
+                config.proxy(inbound).await?;
+            }
+        };
+        Ok(())
+    }
+}
+
+async fn copy<'a, R, W>(reader: &'a mut R, writer: &'a mut W) -> io::Result<u64>
+where
+    R: AsyncRead + Unpin + ?Sized,
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    match io::copy(reader, writer).await {
+        Ok(u64) => {
+            let _ = writer.shutdown().await;
+            Ok(u64)
+        }
+        Err(_) => Ok(0),
+    }
+}

src/upstreams/proxy_to_upstream.rs

@@ -0,0 +1,57 @@
+use crate::servers::upstream_address::UpstreamAddress;
+
+use crate::upstreams::copy;
+use futures::future::try_join;
+use log::{debug, error};
+use serde::Deserialize;
+use std::net::SocketAddr;
+use tokio::io;
+use tokio::net::TcpStream;
+
+#[derive(Debug, Clone, Deserialize, Default)]
+pub struct ProxyToUpstream {
+    pub addr: String,
+    pub protocol: String,
+    #[serde(skip_deserializing)]
+    addresses: UpstreamAddress,
+}
+
+impl ProxyToUpstream {
+    pub async fn resolve_addresses(&self) -> std::io::Result<Vec<SocketAddr>> {
+        self.addresses.resolve((*self.protocol).into()).await
+    }
+
+    pub fn new(address: String, protocol: String) -> Self {
+        Self {
+            addr: address.clone(),
+            protocol,
+            addresses: UpstreamAddress::new(address),
+        }
+    }
+
+    pub(crate) async fn proxy(&self, inbound: TcpStream) -> Result<(), Box<dyn std::error::Error>> {
+        let outbound = match self.protocol.as_ref() {
+            "tcp4" | "tcp6" | "tcp" => {
+                TcpStream::connect(self.resolve_addresses().await?.as_slice()).await?
+            }
+            _ => {
+                error!("Reached unknown protocol: {:?}", self.protocol);
+                return Err("Reached unknown protocol".into());
+            }
+        };
+
+        debug!("Connected to {:?}", outbound.peer_addr().unwrap());
+
+        let (mut ri, mut wi) = io::split(inbound);
+        let (mut ro, mut wo) = io::split(outbound);
+
+        let inbound_to_outbound = copy(&mut ri, &mut wo);
+        let outbound_to_inbound = copy(&mut ro, &mut wi);
+
+        let (bytes_tx, bytes_rx) = try_join(inbound_to_outbound, outbound_to_inbound).await?;
+
+        debug!("Bytes read: {:?} write: {:?}", bytes_tx, bytes_rx);
+
+        Ok(())
+    }
+}

tests/config.yaml

@@ -19,16 +19,6 @@ servers:
     listen:
       - "0.0.0.0:54956"
     default: echo
-  kcp_server:
-    protocol: kcp
-    listen:
-      - "127.0.0.1:54958"
-    default: tester
-  kcp_echo_server:
-    protocol: kcp
-    listen:
-      - "127.0.0.1:54959"
-    default: echo
 
 upstream:
   web: "tcp://127.0.0.1:8080"