RealM

A network relay tool

Introduction

Realm is a simple, high performance relay server written in rust.

Features

• Zero configuration. Setup and run in one command.
• Concurrency. Bidirectional concurrent traffic leads to high performance.
• Low resources cost.

Build

Install rust toolchains with rustup.

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Clone this repository

git clone https://github.com/zephyrchien/realm

Enter the directory and build

cd realm
git submodule sync && git submodule update --init --recursive
cargo build --release

Build options

• udp (enabled by default)
• trust-dns (enabled by default)
• zero-copy (enabled on linux)
• multi-thread (enabled by default)
• tfo
• mi-malloc
• jemalloc

See also: Cargo.toml

Examples:

# simple tcp
cargo build --release --no-default-features

# enable other options
cargo build --release --no-default-features --features udp, tfo, zero-copy, trust-dns

安装脚本

脚本根据 seal0207 版修改

国外

wget -N --no-check-certificate https://raw.githubusercontent.com/xOS/RealM/master/realm.sh && chmod +x realm.sh && ./realm.sh

国内

wget -N --no-check-certificate https://cdn.jsdelivr.net/gh/xOS/RealM@master/realm.sh && chmod +x realm.sh && ./realm.sh

Usage

Realm 2.0.0 [udp][zero-copy][trust-dns][proxy-protocol][multi-thread]
A high efficiency relay tool

USAGE:
    realm [FLAGS] [OPTIONS]

FLAGS:
    -h, --help       show help
    -v, --version    show version
    -d, --daemon     run as a unix daemon
    -u, --udp        force enable udp forward
    -f, --tfo        force enable tcp fast open
    -z, --splice     force enable tcp zero copy

OPTIONS:
    -n, --nofile <limit>        set nofile limit
    -p, --page <number>         set pipe capacity
    -c, --config <path>         use config file
    -l, --listen <address>      listen address
    -r, --remote <address>      remote address
    -x, --through <address>     send through ip or address
    -i, --interface <device>    bind to interface

LOG OPTIONS:
        --log-level <level>    override log level
        --log-output <path>    override log output

DNS OPTIONS:
        --dns-mode <mode>            override dns mode
        --dns-min-ttl <second>       override dns min ttl
        --dns-max-ttl <second>       override dns max ttl
        --dns-cache-size <number>    override dns cache size
        --dns-protocol <protocol>    override dns protocol
        --dns-servers <servers>      override dns servers

PROXY OPTIONS:
        --send-proxy                       send proxy protocol header
        --send-proxy-version <version>     send proxy protocol version
        --accept-proxy                     accept proxy protocol header
        --accept-proxy-timeout <second>    accept proxy protocol timeout

TIMEOUT OPTIONS:
        --tcp-timeout <second>    override tcp timeout
        --udp-timeout <second>    override udp timeout

SUBCOMMANDS:
    convert    convert your legacy configuration into an advanced one

Start from command line arguments:

realm -l 0.0.0.0:5000 -r 1.1.1.1:443

Start with a config file:

# use toml
realm -c config.toml

# use json
realm -c config.json

Start with environment variables:

REALM_CONF='{"endpoints":[{"local":"127.0.0.1:5000","remote":"1.1.1.1:443"}]}' realm

# or
export REALM_CONF=`cat config.json | jq -c `
realm

Convert a legacy config file:

realm convert old.json

Configuration

TOML Example

[log]
level = "warn"
output = "/var/log/realm.log"

[network]
use_udp = true
zero_copy = true

[[endpoints]]
listen = "0.0.0.0:5000"
remote = "1.1.1.1:443"

[[endpoints]]
listen = "0.0.0.0:10000"
remote = "www.google.com:443"

JSON Example

{
  "log": {
    "level": "warn",
    "output": "/var/log/realm.log"
  },
  "network": {
    "use_udp": true,
    "zero_copy": true
  },
  "endpoints": [
    {
      "listen": "0.0.0.0:5000",
      "remote": "1.1.1.1:443"
    },
    {
      "listen": "0.0.0.0:10000",
      "remote": "www.google.com:443"
    }
  ]
}

See other examples here

global

├── log
│   ├── level
│   └── output
├── dns
│   ├── mode
│   ├── protocol
│   ├── nameservers
│   ├── min_ttl
│   ├── max_ttl
│   └── cache_size
├── network
│   ├── use_udp
│   ├── zero_copy
│   ├── fast_open
│   ├── tcp_timeout
│   ├── udp_timeout
│   ├── send_proxy
│   ├── send_proxy_version
│   ├── accept_proxy
│   └── accept_proxy_timeout
└── endpoints
    ├── listen
    ├── remote
    ├── through
    ├── interface
    └── network

You should provide at least endpoint.listen and endpoint.remote, the left fields will take their default values.

Option priority: cmd override > endpoint config > global config

log

log.level: string

values:

• off
• error
• warn
• info
• debug
• trace

default: off

log.output: string

values:

• stdout
• stderr
• path (e.g. /var/log/realm.log)

default: stdout

dns

Require the trust-dns feature

dns.mode: string

Dns resolve strategy.

values:

• ipv4_only
• ipv6_only
• ipv4_then_ipv6
• ipv6_then_ipv4
• ipv4_and_ipv6

default: ipv4_and_ipv6

dns.protocol: string

Dns transport protocol.

values:

• tcp
• udp
• tcp_and_udp

default: tcp_and_udp

dns.nameservers: string array

Custom upstream servers.

format: ["server1", "server2" ...]

default:

If on unix/windows, read from the default location.(e.g. /etc/resolv.conf).

Otherwise, use google's public dns(8.8.8.8:53, 8.8.4.4:53 and 2001:4860:4860::8888:53, 2001:4860:4860::8844:53).

dns.min_ttl: unsigned int

The minimum lifetime of a positive dns cache

default: 0

dns.max_ttl: unsigned int

The maximum lifetime of a positive dns cache

default: 86400 (1 day)

dns.cache_size: unsigned int

The maximum count of dns cache

default: 32

network

network.use_udp: bool

Require the udp feature

Start listening on a udp endpoint and forward packets to the remote peer.

It will dynamically allocate local endpoints and establish udp associations. Once timeout, the endpoints will be deallocated and the association will be terminated. See also: network.udp_timeout

Due to the receiver side not limiting access to the association, the relay works like a full-cone NAT.

default: false

network.zero_copy: bool

Require the zero-copy feature

Use splice instead of send/recv while handing tcp connection. This will save a lot of memory copies and context switches.

default: false

network.fast_open: bool

Require the fast-open feature

It is not recommended to enable this option, see The Sad Story of TCP Fast Open.

default: false

network.tcp_tomeout: unsigned int

Close the connection if the peer does not send any data during timeout.

This option remains unimplemented! (since ce5213)

To disable timeout, you need to explicitly set timeout value to 0.

default: 300

network.udp_timeout: unsigned int

Terminate udp association after timeout.

The timeout value must be properly configured in case of memory leak. Do not use a large timeout!

default: 30

network.send_proxy: bool

Requires the proxy-protocol feature

Send haproxy PROXY header once the connection established. Both v1 and v2 are supported, see send_proxy_version.

You should make sure the remote peer also speaks proxy-protocol.

default: false

network.send_proxy_version: unsigned int

Requires the proxy-protocol feature

This option has no effect unless send_proxy is enabled.

value:

• 1
• 2

default: 2

network.accept_proxy: bool

Requires the proxy-protocol feature

Wait for PROXY header once the connection established.

If the remote sender does not send a v1 or v2 header before other contents, the connection will be closed.

default: false

endpoint

endpoint.listen: string

Local address, supported formats:

• ipv4:port
• ipv6:port

endpoint.remote: string

Remote address, supported formats:

• ipv4:port
• ipv6:port
• example.com:port

endpoint.through: string

TCP: Bind a specific ip before opening a connection

UDP: Bind a specific ip or address before sending packet

Supported formats:

• ipv4/ipv6 (tcp/udp)
• ipv4/ipv6:port (udp)

endpoint.interface: string

Bind to a specific interface

endpoint.network

The same as network, override global options.