Feature: experimental support snell

README.md

@@ -73,7 +73,8 @@ For example, you can use the current directory as the configuration directory:
 $ clash -d .
 ```
 
-Below is an example configuration file:
+<details>
+  <summary>This is an example configuration file</summary>
 
 ```yml
 # port of HTTP
@@ -91,7 +92,7 @@ allow-lan: false
 # "*": bind all IP addresses
 # 192.168.122.11: bind a single IPv4 address
 # "[aaaa::a8aa:ff:fe09:57d8]": bind a single IPv6 address
-bind-address: "*"
+# bind-address: "*"
 
 # Rule / Global/ Direct (default is Rule)
 mode: Rule
@@ -151,9 +152,15 @@ Proxy:
 #   aes-128-ctr aes-192-ctr aes-256-ctr
 #   rc4-md5 chacha20 chacha20-ietf xchacha20
 #   chacha20-ietf-poly1305 xchacha20-ietf-poly1305
-- { name: "ss1", type: ss, server: server, port: 443, cipher: chacha20-ietf-poly1305, password: "password", udp: true }
+- name: "ss1"
+  type: ss
+  server: server
+  port: 443
+  cipher: chacha20-ietf-poly1305
+  password: "password"
+  # udp: true
 
-# old obfs configuration remove after prerelease
+# old obfs configuration format remove after prerelease
 - name: "ss2"
   type: ss
   server: server
@@ -184,47 +191,92 @@ Proxy:
 
 # vmess
 # cipher support auto/aes-128-gcm/chacha20-poly1305/none
-- { name: "vmess", type: vmess, server: server, port: 443, uuid: uuid, alterId: 32, cipher: auto }
+- name: "vmess"
-# with tls
+  type: vmess
-- { name: "vmess", type: vmess, server: server, port: 443, uuid: uuid, alterId: 32, cipher: auto, tls: true }
+  server: server
-# with tls and skip-cert-verify
+  port: 443
-- { name: "vmess", type: vmess, server: server, port: 443, uuid: uuid, alterId: 32, cipher: auto, tls: true, skip-cert-verify: true }
+  uuid: uuid
-# with ws-path and ws-headers
+  alterId: 32
-- { name: "vmess", type: vmess, server: server, port: 443, uuid: uuid, alterId: 32, cipher: auto, network: ws, ws-path: /path, ws-headers: { Host: v2ray.com } }
+  cipher: auto
-# with ws + tls
+  # udp: true
-- { name: "vmess", type: vmess, server: server, port: 443, uuid: uuid, alterId: 32, cipher: auto, network: ws, ws-path: /path, tls: true }
+  # tls: true
+  # skip-cert-verify: true
+  # network: ws
+  # ws-path: /path
+  # ws-headers:
+  #   Host: v2ray.com
 
 # socks5
-- { name: "socks", type: socks5, server: server, port: 443 }
+- name: "socks"
-# socks5 with authentication
+  type: socks5
-- { name: "socks", type: socks5, server: server, port: 443, username: "username", password: "password" }
+  server: server
-# with tls
+  port: 443
-- { name: "socks", type: socks5, server: server, port: 443, tls: true }
+  # username: username
-# with tls and skip-cert-verify
+  # password: password
-- { name: "socks", type: socks5, server: server, port: 443, tls: true, skip-cert-verify: true }
+  # tls: true
+  # skip-cert-verify: true
+  # udp: true
 
 # http
-- { name: "http", type: http, server: server, port: 443 }
+- name: "http"
-# http with authentication
+  type: http
-- { name: "http", type: http, server: server, port: 443, username: "username", password: "password" }
+  server: server
-# with tls (https)
+  port: 443
-- { name: "http", type: http, server: server, port: 443, tls: true }
+  # username: username
-# with tls (https) and skip-cert-verify
+  # password: password
-- { name: "http", type: http, server: server, port: 443, tls: true, skip-cert-verify: true }
+  # tls: true # https
+  # skip-cert-verify: true
+
+# snell
+- name: "snell"
+  type: snell
+  server: server
+  port: 44046
+  psk: yourpsk
+  # obfs-opts:
+    # mode: http # or tls
+    # host: bing.com
 
 Proxy Group:
 # url-test select which proxy will be used by benchmarking speed to a URL.
-- { name: "auto", type: url-test, proxies: ["ss1", "ss2", "vmess1"], url: "http://www.gstatic.com/generate_204", interval: 300 }
+- name: "auto"
+  type: url-test
+  proxies:
+    - ss1
+    - ss2
+    - vmess1
+  url: 'http://www.gstatic.com/generate_204'
+  interval: 300
 
 # fallback select an available policy by priority. The availability is tested by accessing an URL, just like an auto url-test group.
-- { name: "fallback-auto", type: fallback, proxies: ["ss1", "ss2", "vmess1"], url: "http://www.gstatic.com/generate_204", interval: 300 }
+- name: "fallback-auto"
+  type: fallback
+  proxies:
+    - ss1
+    - ss2
+    - vmess1
+  url: 'http://www.gstatic.com/generate_204'
+  interval: 300
 
 # load-balance: The request of the same eTLD will be dial on the same proxy.
-- { name: "load-balance", type: load-balance, proxies: ["ss1", "ss2", "vmess1"], url: "http://www.gstatic.com/generate_204", interval: 300 }
+- name: "load-balance"
+  type: load-balance
+  proxies:
+    - ss1
+    - ss2
+    - vmess1
+  url: 'http://www.gstatic.com/generate_204'
+  interval: 300
 
 # select is used for selecting proxy or proxy group
 # you can use RESTful API to switch proxy, is recommended for use in GUI.
-- { name: "Proxy", type: select, proxies: ["ss1", "ss2", "vmess1", "auto"] }
+- name: Proxy
+  type: select
+  proxies:
+    - ss1
+    - ss2
+    - vmess1
+    - auto
 
 Rule:
 - DOMAIN-SUFFIX,google.com,auto
@@ -241,6 +293,7 @@ Rule:
 # you also can use `FINAL,Proxy` or `FINAL,,Proxy` now
 - MATCH,auto
 ```
+</details>
 
 ## Documentations
 https://clash.gitbook.io/

adapters/outbound/snell.go

@@ -0,0 +1,71 @@
+package adapters
+
+import (
+	"fmt"
+	"net"
+	"strconv"
+
+	"github.com/Dreamacro/clash/common/structure"
+	obfs "github.com/Dreamacro/clash/component/simple-obfs"
+	"github.com/Dreamacro/clash/component/snell"
+	C "github.com/Dreamacro/clash/constant"
+)
+
+type Snell struct {
+	*Base
+	server     string
+	psk        []byte
+	obfsOption *simpleObfsOption
+}
+
+type SnellOption struct {
+	Name     string                 `proxy:"name"`
+	Server   string                 `proxy:"server"`
+	Port     int                    `proxy:"port"`
+	Psk      string                 `proxy:"psk"`
+	ObfsOpts map[string]interface{} `proxy:"obfs-opts,omitempty"`
+}
+
+func (s *Snell) Dial(metadata *C.Metadata) (C.Conn, error) {
+	c, err := dialTimeout("tcp", s.server, tcpTimeout)
+	if err != nil {
+		return nil, fmt.Errorf("%s connect error: %s", s.server, err.Error())
+	}
+	tcpKeepAlive(c)
+	switch s.obfsOption.Mode {
+	case "tls":
+		c = obfs.NewTLSObfs(c, s.obfsOption.Host)
+	case "http":
+		_, port, _ := net.SplitHostPort(s.server)
+		c = obfs.NewHTTPObfs(c, s.obfsOption.Host, port)
+	}
+	c = snell.StreamConn(c, s.psk)
+	port, _ := strconv.Atoi(metadata.DstPort)
+	err = snell.WriteHeader(c, metadata.String(), uint(port))
+	return newConn(c, s), err
+}
+
+func NewSnell(option SnellOption) (*Snell, error) {
+	server := net.JoinHostPort(option.Server, strconv.Itoa(option.Port))
+	psk := []byte(option.Psk)
+
+	decoder := structure.NewDecoder(structure.Option{TagName: "obfs", WeaklyTypedInput: true})
+	obfsOption := &simpleObfsOption{Host: "bing.com"}
+	if err := decoder.Decode(option.ObfsOpts, obfsOption); err != nil {
+		return nil, fmt.Errorf("snell %s initialize obfs error: %s", server, err.Error())
+	}
+
+	if obfsOption.Mode != "tls" && obfsOption.Mode != "http" {
+		return nil, fmt.Errorf("snell %s obfs mode error: %s", server, obfsOption.Mode)
+	}
+
+	return &Snell{
+		Base: &Base{
+			name: option.Name,
+			tp:   C.Snell,
+		},
+		server:     server,
+		psk:        psk,
+		obfsOption: obfsOption,
+	}, nil
+}

component/snell/cipher.go

@@ -0,0 +1,21 @@
+package snell
+
+import (
+	"crypto/cipher"
+
+	"golang.org/x/crypto/argon2"
+)
+
+type snellCipher struct {
+	psk      []byte
+	makeAEAD func(key []byte) (cipher.AEAD, error)
+}
+
+func (sc *snellCipher) KeySize() int  { return 32 }
+func (sc *snellCipher) SaltSize() int { return 16 }
+func (sc *snellCipher) Encrypter(salt []byte) (cipher.AEAD, error) {
+	return sc.makeAEAD(argon2.IDKey(sc.psk, salt, 3, 8, 1, uint32(sc.KeySize())))
+}
+func (sc *snellCipher) Decrypter(salt []byte) (cipher.AEAD, error) {
+	return sc.makeAEAD(argon2.IDKey(sc.psk, salt, 3, 8, 1, uint32(sc.KeySize())))
+}

component/snell/snell.go

@@ -0,0 +1,91 @@
+package snell
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"io"
+	"net"
+	"sync"
+
+	"github.com/Dreamacro/go-shadowsocks2/shadowaead"
+	"golang.org/x/crypto/chacha20poly1305"
+)
+
+const (
+	CommandPing    byte = 0
+	CommandConnect byte = 1
+
+	CommandTunnel byte = 0
+	CommandError  byte = 2
+
+	Version byte = 1
+)
+
+var (
+	bufferPool = sync.Pool{New: func() interface{} { return &bytes.Buffer{} }}
+)
+
+type Snell struct {
+	net.Conn
+	buffer [1]byte
+	reply  bool
+}
+
+func (s *Snell) Read(b []byte) (int, error) {
+	if s.reply {
+		return s.Conn.Read(b)
+	}
+
+	s.reply = true
+	if _, err := io.ReadFull(s.Conn, s.buffer[:]); err != nil {
+		return 0, err
+	}
+
+	if s.buffer[0] == CommandTunnel {
+		return s.Conn.Read(b)
+	} else if s.buffer[0] != CommandError {
+		return 0, errors.New("Command not support")
+	}
+
+	// CommandError
+	if _, err := io.ReadFull(s.Conn, s.buffer[:]); err != nil {
+		return 0, err
+	}
+
+	length := int(s.buffer[0])
+	msg := make([]byte, length)
+
+	if _, err := io.ReadFull(s.Conn, msg); err != nil {
+		return 0, err
+	}
+
+	return 0, errors.New(string(msg))
+}
+
+func WriteHeader(conn net.Conn, host string, port uint) error {
+	buf := bufferPool.Get().(*bytes.Buffer)
+	buf.Reset()
+	defer bufferPool.Put(buf)
+	buf.WriteByte(Version)
+	buf.WriteByte(CommandConnect)
+
+	// clientID length & id
+	buf.WriteByte(0)
+
+	// host & port
+	buf.WriteByte(uint8(len(host)))
+	buf.WriteString(host)
+	binary.Write(buf, binary.BigEndian, uint16(port))
+
+	if _, err := conn.Write(buf.Bytes()); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func StreamConn(conn net.Conn, psk []byte) net.Conn {
+	cipher := &snellCipher{psk, chacha20poly1305.New}
+	return &Snell{Conn: shadowaead.NewConn(conn, cipher)}
+}

config/config.go

@@ -300,6 +300,13 @@ func parseProxies(cfg *rawConfig) (map[string]C.Proxy, error) {
 				break
 			}
 			proxy, err = adapters.NewVmess(*vmessOption)
+		case "snell":
+			snellOption := &adapters.SnellOption{}
+			err = decoder.Decode(mapping, snellOption)
+			if err != nil {
+				break
+			}
+			proxy, err = adapters.NewSnell(*snellOption)
 		default:
 			return nil, fmt.Errorf("Unsupport proxy type: %s", proxyType)
 		}

constant/adapters.go

@@ -14,6 +14,7 @@ const (
 	Reject
 	Selector
 	Shadowsocks
+	Snell
 	Socks5
 	Http
 	URLTest
@@ -92,6 +93,8 @@ func (at AdapterType) String() string {
 		return "Selector"
 	case Shadowsocks:
 		return "Shadowsocks"
+	case Snell:
+		return "Snell"
 	case Socks5:
 		return "Socks5"
 	case Http: