Merge pull request #98 from Jigsaw-Code/bemasc-prefix

Use the specified prefix for the connectivity checks

Author: Benjamin M. Schwartz

outline/android/tun2socks.go

@@ -15,13 +15,11 @@
 package tun2socks
 
 import (
-	"fmt"
-	"math"
 	"runtime/debug"
 
 	"github.com/Jigsaw-Code/outline-go-tun2socks/outline"
+	"github.com/Jigsaw-Code/outline-go-tun2socks/outline/shadowsocks"
 	"github.com/Jigsaw-Code/outline-go-tun2socks/tunnel"
-	"github.com/Jigsaw-Code/outline-ss-server/client"
 	"github.com/eycorsican/go-tun2socks/common/log"
 )
 
@@ -40,32 +38,20 @@ type OutlineTunnel interface {
 // Returns an OutlineTunnel instance and does *not* take ownership of the TUN file descriptor; the
 // caller is responsible for closing after OutlineTunnel disconnects.
 //
-// `fd` is the TUN device.  The OutlineTunnel acquires an additional reference to it, which
+//   - `fd` is the TUN device.  The OutlineTunnel acquires an additional reference to it, which
 //     is released by OutlineTunnel.Disconnect(), so the caller must close `fd` _and_ call
 //     Disconnect() in order to close the TUN device.
-// `host` is  IP address of the Shadowsocks proxy server.
-// `port` is the port of the Shadowsocks proxy server.
-// `password` is the password of the Shadowsocks proxy.
-// `cipher` is the encryption cipher the Shadowsocks proxy.
-// `prefix` is the salt prefix to use for TCP connections (optional, use with care).
-// `isUDPEnabled` indicates whether the tunnel and/or network enable UDP proxying.
+//   - `client` is the Shadowsocks client (created by [shadowsocks.NewClient]).
+//   - `isUDPEnabled` indicates whether the tunnel and/or network enable UDP proxying.
 //
 // Throws an exception if the TUN file descriptor cannot be opened, or if the tunnel fails to
 // connect.
-func ConnectShadowsocksTunnel(fd int, host string, port int, password, cipher string, prefix []byte, isUDPEnabled bool) (OutlineTunnel, error) {
-	if port <= 0 || port > math.MaxUint16 {
-		return nil, fmt.Errorf("Invalid port number: %v", port)
-	}
+func ConnectShadowsocksTunnel(fd int, client *shadowsocks.Client, isUDPEnabled bool) (OutlineTunnel, error) {
 	tun, err := tunnel.MakeTunFile(fd)
 	if err != nil {
 		return nil, err
 	}
-	ssclient, err := client.NewClient(host, port, password, cipher)
-	if err != nil {
-		return nil, fmt.Errorf("failed to construct Shadowsocks client: %v", err)
-	}
-	ssclient.SetTCPSaltGenerator(client.NewPrefixSaltGenerator(prefix))
-	t, err := outline.NewTunnel(ssclient, isUDPEnabled, tun)
+	t, err := outline.NewTunnel(client, isUDPEnabled, tun)
 	if err != nil {
 		return nil, err
 	}

outline/apple/tun2socks.go

@@ -16,14 +16,12 @@ package tun2socks
 
 import (
 	"errors"
-	"fmt"
 	"io"
-	"math"
 	"runtime/debug"
 	"time"
 
 	"github.com/Jigsaw-Code/outline-go-tun2socks/outline"
-	"github.com/Jigsaw-Code/outline-ss-server/client"
+	"github.com/Jigsaw-Code/outline-go-tun2socks/outline/shadowsocks"
 )
 
 // OutlineTunnel embeds the tun2socks.Tunnel interface so it gets exported by gobind.
@@ -54,24 +52,15 @@ func init() {
 // Returns an OutlineTunnel instance that should be used to input packets to the tunnel.
 //
 // `tunWriter` is used to output packets to the TUN (VPN).
-// `host` is  IP address of the Shadowsocks proxy server.
-// `port` is the port of the Shadowsocks proxy server.
-// `password` is the password of the Shadowsocks proxy.
-// `cipher` is the encryption cipher the Shadowsocks proxy.
-// `prefix` is the salt prefix to use for TCP connections (optional, use with care).
+// `client` is the Shadowsocks client (created by [shadowsocks.NewClient]).
 // `isUDPEnabled` indicates whether the tunnel and/or network enable UDP proxying.
 //
 // Sets an error if the tunnel fails to connect.
-func ConnectShadowsocksTunnel(tunWriter TunWriter, host string, port int, password, cipher string, prefix []byte, isUDPEnabled bool) (OutlineTunnel, error) {
+func ConnectShadowsocksTunnel(tunWriter TunWriter, client *shadowsocks.Client, isUDPEnabled bool) (OutlineTunnel, error) {
 	if tunWriter == nil {
-		return nil, errors.New("Must provide a TunWriter")
-	} else if port <= 0 || port > math.MaxUint16 {
-		return nil, fmt.Errorf("Invalid port number: %v", port)
+		return nil, errors.New("must provide a TunWriter")
+	} else if client == nil {
+		return nil, errors.New("must provide a client")
 	}
-	ssclient, err := client.NewClient(host, port, password, cipher)
-	if err != nil {
-		return nil, fmt.Errorf("failed to construct Shadowsocks client: %v", err)
-	}
-	ssclient.SetTCPSaltGenerator(client.NewPrefixSaltGenerator(prefix))
-	return outline.NewTunnel(ssclient, isUDPEnabled, tunWriter)
+	return outline.NewTunnel(client, isUDPEnabled, tunWriter)
 }

outline/electron/main.go

@@ -18,7 +18,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"net/url"
 	"os"
 	"os/signal"
 	"strings"
@@ -27,7 +26,6 @@ import (
 
 	oss "github.com/Jigsaw-Code/outline-go-tun2socks/outline/shadowsocks"
 	"github.com/Jigsaw-Code/outline-go-tun2socks/shadowsocks"
-	"github.com/Jigsaw-Code/outline-ss-server/client"
 	"github.com/eycorsican/go-tun2socks/common/log"
 	_ "github.com/eycorsican/go-tun2socks/common/log/simple" // Register a simple logger.
 	"github.com/eycorsican/go-tun2socks/core"
@@ -70,7 +68,7 @@ func main() {
 	args.proxyPort = flag.Int("proxyPort", 0, "Shadowsocks proxy port number")
 	args.proxyPassword = flag.String("proxyPassword", "", "Shadowsocks proxy password")
 	args.proxyCipher = flag.String("proxyCipher", "chacha20-ietf-poly1305", "Shadowsocks proxy encryption cipher")
-	args.proxyPrefix = flag.String("proxyPrefix", "", "Shadowsocks connection prefix, URI-encoded (unsafe)")
+	args.proxyPrefix = flag.String("proxyPrefix", "", "Shadowsocks connection prefix, UTF8-encoded (unsafe)")
 	args.logLevel = flag.String("logLevel", "info", "Logging level: debug|info|warn|error|none")
 	args.dnsFallback = flag.Bool("dnsFallback", false, "Enable DNS fallback over TCP (overrides the UDP handler).")
 	args.checkConnectivity = flag.Bool("checkConnectivity", false, "Check the proxy TCP and UDP connectivity and exit.")
@@ -100,8 +98,33 @@ func main() {
 		os.Exit(oss.IllegalConfiguration)
 	}
 
+	config := oss.Config{
+		Host:       *args.proxyHost,
+		Port:       *args.proxyPort,
+		Password:   *args.proxyPassword,
+		CipherName: *args.proxyCipher,
+	}
+
+	// The prefix is an 8-bit-clean byte sequence, stored in the codepoint
+	// values of a unicode string, which arrives here encoded in UTF-8.
+	prefixRunes := []rune(*args.proxyPrefix)
+	config.Prefix = make([]byte, len(prefixRunes))
+	for i, r := range prefixRunes {
+		if (r & 0xFF) != r {
+			log.Errorf("Character out of range: %r", r)
+			os.Exit(oss.IllegalConfiguration)
+		}
+		config.Prefix[i] = byte(r)
+	}
+
+	client, err := oss.NewClient(&config)
+	if err != nil {
+		log.Errorf("Failed to construct Shadowsocks client: %v", err)
+		os.Exit(oss.IllegalConfiguration)
+	}
+
 	if *args.checkConnectivity {
-		connErrCode, err := oss.CheckConnectivity(*args.proxyHost, *args.proxyPort, *args.proxyPassword, *args.proxyCipher)
+		connErrCode, err := oss.CheckConnectivity(client)
 		log.Debugf("Connectivity checks error code: %v", connErrCode)
 		if err != nil {
 			log.Errorf("Failed to perform connectivity checks: %v", err)
@@ -119,25 +142,14 @@ func main() {
 	// Output packets to TUN device
 	core.RegisterOutputFn(tunDevice.Write)
 
-	ssclient, err := client.NewClient(*args.proxyHost, *args.proxyPort, *args.proxyPassword, *args.proxyCipher)
-	if err != nil {
-		log.Errorf("Failed to construct Shadowsocks client: %v", err)
-		os.Exit(oss.IllegalConfiguration)
-	}
-	prefixBytes, err := url.PathUnescape(*args.proxyPrefix)
-	if err != nil {
-		log.Errorf("\"%s\" could not be URI-decoded", *args.proxyPrefix)
-		os.Exit(oss.IllegalConfiguration)
-	}
-	ssclient.SetTCPSaltGenerator(client.NewPrefixSaltGenerator([]byte(prefixBytes)))
 	// Register TCP and UDP connection handlers
-	core.RegisterTCPConnHandler(shadowsocks.NewTCPHandler(ssclient))
+	core.RegisterTCPConnHandler(shadowsocks.NewTCPHandler(client))
 	if *args.dnsFallback {
 		// UDP connectivity not supported, fall back to DNS over TCP.
 		log.Debugf("Registering DNS fallback UDP handler")
 		core.RegisterUDPConnHandler(dnsfallback.NewUDPHandler())
 	} else {
-		core.RegisterUDPConnHandler(shadowsocks.NewUDPHandler(ssclient, udpTimeout))
+		core.RegisterUDPConnHandler(shadowsocks.NewUDPHandler(client, udpTimeout))
 	}
 
 	// Configure LWIP stack to receive input data from the TUN device

outline/shadowsocks/config.go

@@ -0,0 +1,50 @@
+// Copyright 2022 The Outline Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package shadowsocks
+
+import (
+	"github.com/Jigsaw-Code/outline-ss-server/client"
+	"github.com/eycorsican/go-tun2socks/common/log"
+)
+
+// Config represents a shadowsocks server configuration.
+// Exported via gobind.
+type Config struct {
+	Host       string
+	Port       int
+	Password   string
+	CipherName string
+	Prefix     []byte
+}
+
+// Client provides a transparent container for [client.Client] that
+// is exportable (as an opaque object) via gobind.
+type Client struct {
+	client.Client
+}
+
+// NewClient provides a gobind-compatible wrapper for [client.NewClient].
+func NewClient(config *Config) (*Client, error) {
+	c, err := client.NewClient(config.Host, config.Port, config.Password, config.CipherName)
+	if err != nil {
+		return nil, err
+	}
+	if len(config.Prefix) > 0 {
+		log.Debugf("Using salt prefix: %s", string(config.Prefix))
+		c.SetTCPSaltGenerator(client.NewPrefixSaltGenerator(config.Prefix))
+	}
+
+	return &Client{c}, nil
+}

outline/shadowsocks/connectivity.go

@@ -32,12 +32,7 @@ const reachabilityTimeout = 10 * time.Second
 // the current network. Parallelizes the execution of TCP and UDP checks, selects the appropriate
 // error code to return accounting for transient network failures.
 // Returns an error if an unexpected error ocurrs.
-func CheckConnectivity(host string, port int, password, cipher string) (int, error) {
-	client, err := shadowsocks.NewClient(host, port, password, cipher)
-	if err != nil {
-		// TODO: Inspect error for invalid cipher error or proxy host resolution failure.
-		return Unexpected, err
-	}
+func CheckConnectivity(client *Client) (int, error) {
 	tcpChan := make(chan error)
 	// Check whether the proxy is reachable and that the client is able to authenticate to the proxy
 	go func() {