Leaf

A lightweight and fast proxy utility tries to include any useful features.

Features

Inbounds are proxy servers and outbounds are clients.

• HTTP inbound supports CONNECT method

• SOCKS 5 inbound and outbound with UDP ASSOCIATE support

• TUN inbound

• Trojan inbound and outbound

• Direct outbound sends a proxy request directly to it's destination

• Drop outbound rejects a proxy request

• Shadowsocks outbound

• VMess outbound

• WebSocket inbound and outbound

• TLS outbound

• H2 outbound

• Chain inbound and outbound for chaining other inbounds and outbounds

• Failover outbound tries a proxy request on a group of outbounds one by one

• Random outbound sends a proxy request to one of the outbounds randomly

• Tryall outbound tries a proxy request on a group of outbounds simultaneously

• A router routes requests from inbounds to outbounds base on domain or IP rules

• Full cone NAT

• TUN-based transport proxy

• Fake DNS

• Domain sniffing from TLS traffic enabled by default

• Load balancing / high availability through failover/random/tryall outbounds

Getting Started

A local HTTP server redirects accepted requests to a SOCKS 5 server:

{
    "inbounds": [
        {
            "address": "127.0.0.1",
            "port": 1087,
            "protocol": "http"
        }
    ],
    "log": {
        "level": "trace"
    },
    "outbounds": [
        {
            "protocol": "socks",
            "settings": {
                "address": "127.0.0.1",
                "port": 1080
            }
        }
    ]
}

A SOCKS 5 server sends out accepted requests directly:

{
    "inbounds": [
        {
            "address": "127.0.0.1",
            "port": 1080,
            "protocol": "socks"
        }
    ],
    "log": {
        "level": "trace"
    },
    "outbounds": [
        {
            "protocol": "direct"
        }
    ]
}

Tests the setup:

https_proxy=127.0.0.1:1087 curl "https://example.org"

Usage

You may find some configuration samples here, it also serves as a reference for the JSON config format.

Build

Install Rust: https://www.rust-lang.org/tools/install

Install nightly toolchain:

rustup default nightly

Install a C compiler, e.g. GCC:

apt update && apt install gcc

# Or clang on macOS
# brew update && brew install clang

Clone & Build:

git clone https://github.com/eycorsican/leaf.git
cd leaf
git submodule init
git submodule update
cargo build -p leaf-bin

Run:

./target/debug/leaf -h

Customizing Build

You may build leaf with a selected set of features.

By including only the demanded features, you will get an optimized artifact with smaller binary size and lower runtime memory footprint.

For example, this build command,

cargo build --release --manifest-path leaf-bin/Cargo.toml --no-default-features --features "leaf/config-json leaf/inbound-socks leaf/outbound-direct leaf/outbound-shadowsocks leaf/ring-aead"

will result in an executable supports only the JSON config format, socks inbound, direct and shadowsocks outbounds.

Note that for proxy protocols with AEAD crypto functions, one of the leaf/ring-aead and leaf/openssl-aead features must be included. Similarly, one of the leaf/rustls-tls and leaf/openssl-tls must be included for leaf/outbound-tls feature.

Refer to leaf/Cargo.toml for a full list of available features.

iOS

App Store: https://apps.apple.com/us/app/leaf-lightweight-proxy/id1534109007

TestFlight: https://testflight.apple.com/join/std0FFCS

Demo for Developer: https://github.com/eycorsican/ileaf

OpenWrt

Running as transparent proxy on OpenWrt:

# Install the TUN package.
opkg update && opkg install kmod-tun

# Get the default interface address.
ADDRESS=`ip route get 1 | awk '{print $7;exit}'`

# Get the default gateway address.
GATEWAY=`ip route get 1 | awk '{print $3;exit}'`

TUN_NAME=tun8
TUN_ADDRESS=172.16.0.2
TUN_GATEWAY=172.16.0.1

# Properly configure the config file.
cat <<EOF > cfg.conf
[General]
loglevel = debug
dns-server = 223.5.5.5, 1.1.1.1
dns-interface = $ADDRESS
always-real-ip = *
tun = $TUN_NAME, $TUN_ADDRESS, 255.255.255.0, $TUN_GATEWAY, 1500

[Proxy]
Direct = direct, interface=$ADDRESS
Proxy = ss, 1.2.3.4, 9999, encrypt-method=chacha20-ietf-poly1305, password=9999, interface=$ADDRESS

[Rule]
DOMAIN-SUFFIX, google.com, Proxy
FINAL, Direct
EOF

# Open another SSH session to run leaf with the config.
# It's important to run in a seperate window since we still need
# the variables defined above to continue our setup process.
# I suggest you use `screen`: opkg update && opkg install screen
leaf -c cfg.conf

# Route traffic initiated from leaf to the original gateway.
ip route add default via $GATEWAY table default
ip rule add from $ADDRESS table default

# Route local traffic to TUN.
ip route del default table main
ip route add default via $TUN_GATEWAY

# Route traffic from other deivces to TUN.
iptables -I FORWARD -o $TUN_NAME -j ACCEPT

Re-run:

# Stop leaf via ctrl+c.

# Make some changes to your `cfg.conf`.

# Re-run leaf.
leaf -c cfg.conf

# Re-add the default route to TUN.
ip route add default via $TUN_GATEWAY

Recover the original network:

# Stop leaf via ctrl+c.

# Remove iptables rules.
iptables -D FORWARD -o $TUN_NAME -j ACCEPT

# Cleanup the routing table.
ip rule del from $ADDRESS
ip route del default table default

# Recover the original default route.
ip route add default via $GATEWAY

Check if everything looks fine:

iptables -L FORWARD -n
ip route show table main
ip route show table default
ip rule show