Improve config file handling

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

.drone.jsonnet

@@ -1,4 +1,4 @@
-local executableName = 'fourth';
+local executableName = 'l4p';
 local build_image = 'img.kie.rs/jjkiers/rust-cross:rust1.71.1-zig';
 
 local archs = [

Cargo.lock

@@ -134,24 +134,6 @@ dependencies = [
  "percent-encoding",
 ]
 
-[[package]]
-name = "fourth"
-version = "0.1.7"
-dependencies = [
- "async-trait",
- "byte_string",
- "bytes",
- "futures",
- "log",
- "pretty_env_logger",
- "serde",
- "serde_yaml",
- "time",
- "tls-parser",
- "tokio",
- "url",
-]
-
 [[package]]
 name = "futures"
 version = "0.3.30"
@@ -313,6 +295,24 @@ version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1a46d1a171d865aa5f83f92695765caa047a9b4cbae2cbf37dbd613a793fd4c"
 
+[[package]]
+name = "layer4-proxy"
+version = "0.1.7"
+dependencies = [
+ "async-trait",
+ "byte_string",
+ "bytes",
+ "futures",
+ "log",
+ "pretty_env_logger",
+ "serde",
+ "serde_yaml",
+ "time",
+ "tls-parser",
+ "tokio",
+ "url",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.153"

Cargo.toml

@@ -1,13 +1,13 @@
 [package]
-name = "fourth"
+name = "layer4-proxy"
 version = "0.1.7"
 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"
-repository = "https://github.com/KernelErr/fourth"
+homepage = "https://code.kiers.eu/jjkiers/layer4-proxy"
+repository = "https://code.kiers.eu/jjkiers/layer4-proxy"
 keywords = ["proxy", "network"]
 categories = ["web-programming"]
 
@@ -15,6 +15,10 @@ categories = ["web-programming"]
 
 exclude = [".*"]
 
+[[bin]]
+name = "l4p"
+path = "src/main.rs"
+
 [dependencies]
 async-trait = "0.1.73"
 byte_string = "1"

README-ZH.md

@@ -1,80 +0,0 @@
-# Fourth
-
-> 这一波在第四层。
-
-[![](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)
-
-[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
-
-- 监听指定端口代理到本地或远端指定端口
-- 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
-$ 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。
-
-或者您也可以使用Cargo直接安装：
-
-```bash
-$ 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`，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:
-  proxy_server:
-    listen:
-      - "127.0.0.1:8081"
-    default: remote
-
-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)。
-
-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?
-
-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。

README.md

@@ -1,41 +1,39 @@
-# Fourth
+# l4p
 
 > 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)
 
-**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.
+`l4p` 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)
+- DNS-based backend with periodic resolution
 
 ## 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
+$ cd l4p
 $ cargo build --release
 ```
 
-Binary file will be generated at `target/release/fourth`, or you can use `cargo install --path .` to install.
+Binary file will be generated at `target/release/l4p`, or you can use `cargo install --path .` to install.
 
-Or you can use Cargo to install Fourth:
+Or you can use Cargo to install `l4p`:
 
 ```bash
-$ cargo install fourth
+$ cargo install l4p
 ```
 
 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:
+`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
@@ -51,20 +49,16 @@ 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).
+There are two upstreams built in:
+* Ban, which terminates the connection immediately
+* Echo, which reflects back with the input
 
-## 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
+For detailed configuration, check [this example](./config.yaml.example).
 
 ## Thanks
 
-- [tokio_kcp](https://github.com/Matrix-Zhang/tokio_kcp)
+- [`l4p`](https://crates.io/crates/`l4p`), of which this is a heavily modified fork.
 
 ## License
 
-Fourth is available under terms of Apache-2.0.
+`l4p` is available under terms of Apache-2.0.

config.yaml.example

@@ -2,15 +2,20 @@ version: 1
 log: debug
 
 servers:
-  example_server:
+  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: gh-proxy
+      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

l4p.service

@@ -1,5 +1,5 @@
 [Unit]
-Description=Fourth - Layer 4 proxy
+Description=l4p - Layer 4 proxy
 
 After=network-online.target
 Wants=network-online.target
@@ -11,9 +11,9 @@ WantedBy=default.target
 Type=simple
 
 # Allow read-only access to the config directory
-ReadOnlyPaths=/etc/fourth
+ReadOnlyPaths=/etc/l4p
 # Path to the binary
-ExecStart=/usr/local/bin/fourth
+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

src/main.rs

@@ -7,11 +7,19 @@ use crate::config::ConfigV1;
 use crate::servers::Server;
 
 use log::{debug, error};
-use std::env;
-use std::path::Path;
+use std::path::PathBuf;
 
 fn main() {
-    let config_path = find_config();
+    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,
@@ -29,17 +37,28 @@ fn main() {
     error!("Server ended with errors");
 }
 
-fn find_config() -> String {
-    let config_path =
-        env::var("FOURTH_CONFIG").unwrap_or_else(|_| "/etc/fourth/config.yaml".to_string());
+fn find_config() -> Result<String, Vec<String>> {
+    let possible_paths = ["/etc/l4p", ""];
+    let possible_names = ["l4p.yaml", "config.yaml"];
 
-    if Path::new(&config_path).exists() {
-        return config_path;
+    let mut tried_paths = Vec::<String>::new();
+
+    for path in possible_paths
+        .iter()
+        .flat_map(|&path| {
+            possible_names
+                .iter()
+                .map(move |&file| PathBuf::new().join(path).join(file))
+        })
+        .collect::<Vec<PathBuf>>()
+    {
+        let path_str = path.to_string_lossy().to_string();
+        if path.exists() {
+            return Ok(path_str);
         }
 
-    if Path::new("config.yaml").exists() {
-        return String::from("config.yaml");
+        tried_paths.push(path_str);
     }
 
-    String::from("")
+    Err(tried_paths)
 }