Enable explicit ipv4 / ipv6 proxying

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

.github/workflows/publish-binaries.yml

@@ -0,0 +1,39 @@
+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 }}

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fourth"
-version = "0.1.2"
+version = "0.1.5"
 edition = "2021"
 authors = ["LI Rui <lr_cn@outlook.com>"]
 license = "Apache-2.0"
@@ -19,12 +19,13 @@ exclude = [".*"]
 log = "0.4"
 pretty_env_logger = "0.4"
 serde = { version = "1.0", features = ["derive"] }
-serde_yaml = "0.8"
+serde_yaml = "0.9.21"
 futures = "0.3"
 tls-parser = "0.11"
+url = "2.2.2"
+time = { version = "0.3.1", features = ["local-offset", "formatting"] }
 
 tokio = { version = "1.0", features = ["full"] }
 
 bytes = "1.1"
-kcp = "0.4"
 byte_string = "1"

README-EN.md

@@ -4,6 +4,8 @@
 
 [![](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
@@ -29,36 +31,35 @@ Or you can use Cargo to install Fourth:
 $ 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`, here is an example:
+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:
-  example_server:
+  proxy_server:
-    listen:
-      - "0.0.0.0:443"
-      - "[::]:443"
-    tls: true # Enable TLS features like SNI
-    sni:
-      proxy.example.com: proxy
-      www.example.com: nginx
-    default: ban
-  relay_server:
     listen:
       - "127.0.0.1:8081"
     default: remote
 
 upstream:
-  nginx: "127.0.0.1:8080"
+  remote: "tcp://www.remote.example.com:8082" # proxy to remote address
-  proxy: "127.0.0.1:1024"
-  other: "www.remote.example.com:8082" # proxy to remote address
 ```
 
-Built-in two upstreams: ban(terminate connection immediately), echo
+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
 

README.md

@@ -6,6 +6,8 @@
 
 [English](/README-EN.md)
 
+**积极开发中，0.1版本迭代可能较快**
+
 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）。
 
 ## 功能
@@ -31,41 +33,37 @@ $ cargo build --release
 $ cargo install fourth
 ```
 
+或者您也可以直接从Release中下载二进制文件。
+
 ## 配置
 
-Fourth使用yaml格式的配置文件，默认情况下会读取`/etc/fourth/config.yaml`，如下是一个示例配置。
+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：
 
 ```yaml
 version: 1
 log: info
 
 servers:
-  example_server:
-    listen:
-      - "0.0.0.0:443"
-      - "[::]:443"
-    tls: true # Enable TLS features like SNI filtering
-    sni:
-      proxy.example.com: proxy
-      www.example.com: nginx
-    default: ban
   proxy_server:
     listen:
       - "127.0.0.1:8081"
     default: remote
-  kcp_server:
-    protocol: kcp # default TCP
-    listen:
-      - "127.0.0.1:8082"
-    default: echo
 
 upstream:
-  nginx: "127.0.0.1:8080"
+  remote: "tcp://www.remote.example.com:8082" # proxy to remote address
-  proxy: "127.0.0.1:1024"
-  other: "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）。
+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)。
+
+注意：[::]会默认同时绑定IPv4和IPv6。
+
+## 性能测试
+
+在4C2G的服务器上测试：
+
+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 `）
+
+使用Fourth代理到本地iperf3：8Gbps
 
 ## io_uring?
 

example-config.yaml

@@ -22,6 +22,6 @@ servers:
     default: echo
 
 upstream:
-  nginx: "127.0.0.1:8080"
+  nginx: "tcp://127.0.0.1:8080"
-  proxy: "127.0.0.1:1024"
+  proxy: "tcp://127.0.0.1:1024"
-  other: "www.remote.example.com:8082" # proxy to remote address
+  remote: "tcp://www.remote.example.com:8082" # proxy to remote address

src/config.rs

@@ -1,12 +1,25 @@
-use log::debug;
+use log::{debug, warn};
 use serde::Deserialize;
-use std::collections::HashMap;
+use std::collections::{HashMap, HashSet};
 use std::fs::File;
 use std::io::{Error as IOError, Read};
+use std::net::SocketAddr;
+use tokio::sync::Mutex;
+use url::Url;
+use tokio::time::Instant;
+use time::OffsetDateTime;
 
 #[derive(Debug, Clone)]
 pub struct Config {
-    pub base: BaseConfig,
+    pub base: ParsedConfig,
+}
+
+#[derive(Debug, Default, Deserialize, Clone)]
+pub struct ParsedConfig {
+    pub version: i32,
+    pub log: Option<String>,
+    pub servers: HashMap<String, ServerConfig>,
+    pub upstream: HashMap<String, Upstream>,
 }
 
 #[derive(Debug, Default, Deserialize, Clone)]
@@ -26,6 +39,84 @@ pub struct ServerConfig {
     pub default: Option<String>,
 }
 
+#[derive(Debug, Clone, Deserialize)]
+pub enum Upstream {
+    Ban,
+    Echo,
+    Custom(CustomUpstream),
+}
+
+#[derive(Debug)]
+struct Addr(Mutex<Vec<SocketAddr>>);
+
+impl Default for Addr {
+    fn default() -> Self {
+        Self(Default::default())
+    }
+}
+
+impl Clone for Addr {
+    fn clone(&self) -> Self {
+        tokio::task::block_in_place(|| Self(Mutex::new(self.0.blocking_lock().clone())))
+    }
+}
+
+#[derive(Debug, Clone, Deserialize)]
+pub struct CustomUpstream {
+    pub name: String,
+    pub addr: String,
+    pub protocol: String,
+    #[serde(skip_deserializing)]
+    addresses: Addr,
+}
+
+impl CustomUpstream {
+    pub async fn resolve_addresses(&self) -> std::io::Result<()> {
+        {
+            let addr = self.addresses.0.lock().await;
+            if addr.len() > 0 {
+                debug!("Already have addresses: {:?}", &addr);
+                return Ok(());
+            }
+        }
+
+        debug!("Resolving addresses for {}", &self.addr);
+        let addresses = tokio::net::lookup_host(self.addr.clone()).await?;
+
+        let mut addr: Vec<SocketAddr> = match self.protocol.as_ref() {
+            "tcp4" => addresses.into_iter().filter(|a| a.is_ipv4()).collect(),
+            "tcp6" => addresses.into_iter().filter(|a| a.is_ipv6()).collect(),
+            _ => addresses.collect(),
+        };
+
+        debug!("Got addresses for {}: {:?}", &self.addr, &addr);
+        debug!("Resolved at {}", OffsetDateTime::now_utc().format(&time::format_description::well_known::Rfc3339).expect("Format"));
+
+        {
+            let mut self_addr = self.addresses.0.lock().await;
+            self_addr.clear();
+            self_addr.append(&mut addr);
+        }
+        Ok(())
+    }
+
+    pub async fn get_addresses(&self) -> Vec<SocketAddr> {
+        let a = self.addresses.0.lock().await;
+        a.clone()
+    }
+}
+
+impl Default for CustomUpstream {
+    fn default() -> Self {
+        Self {
+            name: Default::default(),
+            addr: Default::default(),
+            protocol: Default::default(),
+            addresses: Default::default(),
+        }
+    }
+}
+
 #[derive(Debug)]
 pub enum ConfigError {
     IO(IOError),
@@ -41,29 +132,150 @@ impl Config {
     }
 }
 
-fn load_config(path: &str) -> Result<BaseConfig, ConfigError> {
+fn load_config(path: &str) -> Result<ParsedConfig, ConfigError> {
     let mut contents = String::new();
     let mut file = (File::open(path))?;
     (file.read_to_string(&mut contents))?;
 
-    let parsed: BaseConfig = serde_yaml::from_str(&contents)?;
+    let base: BaseConfig = serde_yaml::from_str(&contents)?;
 
-    if parsed.version != 1 {
+    if base.version != 1 {
         return Err(ConfigError::Custom(
             "Unsupported config version".to_string(),
         ));
     }
 
-    let log_level = parsed.log.clone().unwrap_or_else(|| "info".to_string());
+    let log_level = base.log.clone().unwrap_or_else(|| "info".to_string());
     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);
     }
 
-    debug!("Config version {}", parsed.version);
+    debug!("Config version {}", base.version);
 
-    Ok(parsed)
+    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
+                )))
+            }
+        };
+
+        match upstream_url.scheme() {
+            "tcp" | "tcp4" | "tcp6" => {}
+            _ => {
+                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(),
+                ..Default::default()
+            }),
+        );
+    }
+
+    parsed_upstream.insert("ban".to_string(), Upstream::Ban);
+
+    parsed_upstream.insert("echo".to_string(), Upstream::Echo);
+
+    let parsed = ParsedConfig {
+        version: base.version,
+        log: base.log,
+        servers: base.servers,
+        upstream: parsed_upstream,
+    };
+
+    verify_config(parsed)
+}
+
+fn verify_config(config: ParsedConfig) -> Result<ParsedConfig, 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();
+
+    // Check for duplicate upstream names
+    for (name, _) in config.upstream.iter() {
+        if upstream_names.contains(name) {
+            return Err(ConfigError::Custom(format!(
+                "Duplicate upstream name {}",
+                name
+            )));
+        }
+
+        upstream_names.insert(name.to_string());
+    }
+
+    for (_, server) in config.servers.clone() {
+        // check for duplicate listen addresses
+        for listen in server.listen {
+            if listen_addresses.contains(&listen) {
+                return Err(ConfigError::Custom(format!(
+                    "Duplicate listen address {}",
+                    listen
+                )));
+            }
+
+            listen_addresses.insert(listen.to_string());
+        }
+
+        if server.tls.unwrap_or_default() && server.sni.is_some() {
+            for (_, val) in server.sni.unwrap() {
+                used_upstreams.insert(val.to_string());
+            }
+        }
+
+        if server.default.is_some() {
+            used_upstreams.insert(server.default.unwrap().to_string());
+        }
+
+        for key in &used_upstreams {
+            if !config.upstream.contains_key(key) {
+                return Err(ConfigError::Custom(format!("Upstream {} not found", key)));
+            }
+        }
+    }
+
+    for key in &upstream_names {
+        if !used_upstreams.contains(key) && !key.eq("echo") && !key.eq("ban") {
+            warn!("Upstream {} not used", key);
+        }
+    }
+
+    Ok(config)
 }
 
 impl From<IOError> for ConfigError {
@@ -87,7 +299,7 @@ mod tests {
         let config = Config::new("tests/config.yaml").unwrap();
         assert_eq!(config.base.version, 1);
         assert_eq!(config.base.log.unwrap(), "disable");
-        assert_eq!(config.base.servers.len(), 4);
+        assert_eq!(config.base.servers.len(), 5);
-        assert_eq!(config.base.upstream.len(), 3);
+        assert_eq!(config.base.upstream.len(), 3 + 2); // Add ban and echo upstreams
     }
 }

src/main.rs

@@ -6,9 +6,13 @@ use crate::config::Config;
 use crate::servers::Server;
 
 use log::{debug, error};
+use std::env;
 
 fn main() {
-    let config = match Config::new("/etc/fourth/config.yaml") {
+    let config_path =
+        env::var("FOURTH_CONFIG").unwrap_or_else(|_| "/etc/fourth/config.yaml".to_string());
+
+    let config = match Config::new(&config_path) {
         Ok(config) => config,
         Err(e) => {
             println!("Could not load config: {:?}", e);
@@ -20,6 +24,6 @@ fn main() {
     let mut server = Server::new(config.base);
     debug!("{:?}", server);
 
-    let res = server.run();
+    let _ = server.run();
-    error!("Server returned an error: {:?}", res);
+    error!("Server ended with errors");
 }

src/plugins/mod.rs

@@ -1 +1 @@
-pub mod kcp;
+//pub mod kcp;

src/servers/mod.rs

@@ -5,13 +5,13 @@ use std::sync::Arc;
 use tokio::task::JoinHandle;
 
 mod protocol;
-use crate::config::BaseConfig;
+use crate::config::{ParsedConfig, Upstream};
-use protocol::{kcp, tcp};
+use protocol::tcp;
 
 #[derive(Debug)]
 pub struct Server {
     pub proxies: Vec<Arc<Proxy>>,
-    pub config: BaseConfig,
+    pub config: ParsedConfig,
 }
 
 #[derive(Debug, Clone)]
@@ -22,11 +22,11 @@ pub struct Proxy {
     pub tls: bool,
     pub sni: Option<HashMap<String, String>>,
     pub default: String,
-    pub upstream: HashMap<String, String>,
+    pub upstream: HashMap<String, Upstream>,
 }
 
 impl Server {
-    pub fn new(config: BaseConfig) -> Self {
+    pub fn new(config: ParsedConfig) -> Self {
         let mut new_server = Server {
             proxies: Vec::new(),
             config: config.clone(),
@@ -53,6 +53,7 @@ impl Server {
                         continue;
                     }
                 };
+
                 let proxy = Proxy {
                     name: name.clone(),
                     listen: listen_addr,
@@ -82,11 +83,29 @@ impl Server {
             let handle = tokio::spawn(async move {
                 match config.protocol.as_ref() {
                     "tcp" => {
-                        let _ = tcp::proxy(config).await;
+                        let res = tcp::proxy(config.clone()).await;
+                        if res.is_err() {
+                            error!("Failed to start {}: {}", config.name, res.err().unwrap());
                         }
-                    "kcp" => {
-                        let _ = kcp::proxy(config).await;
                     }
+                    "tcp4" => {
+                        let res = tcp::proxy(config.clone()).await;
+                        if res.is_err() {
+                            error!("Failed to start {}: {}", config.name, res.err().unwrap());
+                        }
+                    }
+                    "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)
                     }
@@ -103,13 +122,12 @@ impl Server {
 }
 
 #[cfg(test)]
-mod test {
+mod tests {
-    use crate::plugins::kcp::{KcpConfig, KcpStream};
+    //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::*;
 
@@ -117,13 +135,24 @@ mod test {
     async fn tcp_mock_server() {
         let server_addr: SocketAddr = "127.0.0.1:54599".parse().unwrap();
         let listener = TcpListener::bind(server_addr).await.unwrap();
+        loop {
             let (mut stream, _) = listener.accept().await.unwrap();
+            let mut buf = [0u8; 2];
+            let mut n = stream.read(&mut buf).await.unwrap();
+            while n > 0 {
                 stream.write(b"hello").await.unwrap();
+                if buf.eq(b"by") {
                     stream.shutdown().await.unwrap();
+                    break;
+                }
+                n = stream.read(&mut buf).await.unwrap();
+            }
+            stream.shutdown().await.unwrap();
+        }
     }
 
     #[tokio::test]
-    async fn test_tcp_proxy() {
+    async fn test_proxy() {
         use crate::config::Config;
         let config = Config::new("tests/config.yaml").unwrap();
         let mut server = Server::new(config.base);
@@ -135,44 +164,21 @@ mod test {
             let _ = server.run();
         });
         sleep(Duration::from_secs(1)); // wait for server to start
-        let mut conn = TcpStream::connect("127.0.0.1:54500").await.unwrap();
+
+        // test TCP proxy
+        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();
         conn.read(&mut buf).await.unwrap();
         assert_eq!(&buf, b"hello");
         conn.shutdown().await.unwrap();
-    }
 
-    #[tokio::test]
+        // test TCP echo
-    async fn test_tcp_echo_server() {
+        let mut conn = tokio::net::TcpStream::connect("127.0.0.1:54956")
-        use crate::config::Config;
+            .await
-        let config = Config::new("tests/config.yaml").unwrap();
+            .unwrap();
-        let mut server = Server::new(config.base);
-        thread::spawn(move || {
-            let _ = server.run();
-        });
-        sleep(Duration::from_secs(1)); // wait for server to start
-        let mut conn = TcpStream::connect("127.0.0.1:54956").await.unwrap();
-        let mut buf = [0u8; 1];
-        for i in 0..=255u8 {
-            conn.write(&[i]).await.unwrap();
-            conn.read(&mut buf).await.unwrap();
-            assert_eq!(&buf, &[i]);
-        }
-        conn.shutdown().await.unwrap();
-    }
-
-    #[tokio::test]
-    async fn test_kcp_echo_server() {
-        use crate::config::Config;
-        let config = Config::new("tests/config.yaml").unwrap();
-        let mut server = Server::new(config.base);
-        thread::spawn(move || {
-            let _ = server.run();
-        });
-        sleep(Duration::from_secs(1)); // wait for server to start
-        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();
@@ -180,5 +186,27 @@ mod test {
             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

@@ -1,3 +1,4 @@
+use crate::config::Upstream;
 use crate::plugins::kcp::{KcpConfig, KcpListener, KcpStream};
 use crate::servers::Proxy;
 use futures::future::try_join;
@@ -52,25 +53,30 @@ async fn accept(
                 "No upstream named {:?} on server {:?}",
                 proxy.default, proxy.name
             );
-            return process(inbound, &proxy.default).await;
+            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: &str) -> Result<(), Box<dyn std::error::Error>> {
+async fn process(
-    if upstream == "ban" {
+    mut inbound: KcpStream,
+    upstream: &Upstream,
+) -> Result<(), Box<dyn std::error::Error>> {
+    match upstream {
+        Upstream::Ban => {
             let _ = inbound.shutdown();
-        return Ok(());
+        }
-    } else if upstream == "echo" {
+        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);
-        return Ok(());
         }
-
+        Upstream::Custom(custom) => match custom.protocol.as_ref() {
-    let outbound = TcpStream::connect(upstream).await?;
+            "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);
@@ -78,10 +84,16 @@ async fn process(mut inbound: KcpStream, upstream: &str) -> Result<(), Box<dyn s
                 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?;
+                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(())
 }
 

src/servers/protocol/mod.rs

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

src/servers/protocol/tcp.rs

@@ -1,7 +1,8 @@
+use crate::config::Upstream;
 use crate::servers::protocol::tls::get_sni;
 use crate::servers::Proxy;
 use futures::future::try_join;
-use log::{debug, error, warn};
+use log::{debug, error, info, warn};
 use std::sync::Arc;
 use tokio::io;
 use tokio::io::{AsyncRead, AsyncWrite, AsyncWriteExt};
@@ -33,7 +34,7 @@ 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>> {
-    debug!("New connection from {:?}", inbound.peer_addr()?);
+    info!("New connection from {:?}", inbound.peer_addr()?);
 
     let upstream_name = match proxy.tls {
         false => proxy.default.clone(),
@@ -71,25 +72,46 @@ async fn accept(inbound: TcpStream, proxy: Arc<Proxy>) -> Result<(), Box<dyn std
                 "No upstream named {:?} on server {:?}",
                 proxy.default, proxy.name
             );
-            return process(inbound, &proxy.default).await;
+            return process(inbound, proxy.upstream.get(&proxy.default).unwrap().clone()).await;
+            // ToDo: Remove unwrap and check default option
         }
     };
-    return process(inbound, upstream).await;
+
+    match upstream {
+        Upstream::Custom(u) => u.resolve_addresses().await?,
+        _ => {}
     }
 
-async fn process(mut inbound: TcpStream, upstream: &str) -> Result<(), Box<dyn std::error::Error>> {
+    return process(inbound, upstream.clone()).await;
-    if upstream == "ban" {
+}
+
+async fn process(
+    mut inbound: TcpStream,
+    upstream: Upstream,
+) -> Result<(), Box<dyn std::error::Error>> {
+    match upstream {
+        Upstream::Ban => {
             let _ = inbound.shutdown();
-        return Ok(());
+        }
-    } else if upstream == "echo" {
+        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);
-        return Ok(());
         }
+        Upstream::Custom(custom) => {
+            custom.resolve_addresses().await?;
+            let outbound = match custom.protocol.as_ref() {
+                "tcp4" | "tcp6" | "tcp" => {
+                    TcpStream::connect(custom.get_addresses().await.as_slice()).await?
+                }
+                _ => {
+                    error!("Reached unknown protocol: {:?}", custom.protocol);
+                    return Err("Reached unknown protocol".into());
+                }
+            };
 
-    let outbound = TcpStream::connect(upstream).await?;
+            debug!("Connected to {:?}", outbound.peer_addr().unwrap());
 
             let (mut ri, mut wi) = io::split(inbound);
             let (mut ro, mut wo) = io::split(outbound);
@@ -100,7 +122,8 @@ async fn process(mut inbound: TcpStream, upstream: &str) -> Result<(), Box<dyn s
             let (bytes_tx, bytes_rx) = try_join(inbound_to_outbound, outbound_to_inbound).await?;
 
             debug!("Bytes read: {:?} write: {:?}", bytes_tx, bytes_rx);
-
+        }
+    };
     Ok(())
 }
 

src/servers/protocol/tls.rs

@@ -49,6 +49,7 @@ pub fn get_sni(buf: &[u8]) -> Vec<String> {
         }
     }
 
+    debug!("Found SNIs: {:?}", &snis);
     snis
 }
 

tests/config.yaml

@@ -11,21 +11,26 @@ servers:
       proxy.test.com: proxy
       www.test.com: web
     default: ban
-  echo_server:
-    listen:
-      - "0.0.0.0:54956"
-    default: echo
   tcp_server:
     listen:
       - "127.0.0.1:54500"
     default: tester
+  tcp_echo_server:
+    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: "127.0.0.1:8080"
+  web: "tcp://127.0.0.1:8080"
-  proxy: "www.example.com:1024"
+  proxy: "tcp://www.example.com:1024"
-  tester: "127.0.0.1:54599"
+  tester: "tcp://127.0.0.1:54599"