Add command line client with SOCKS

cmd/client/client.go

@@ -0,0 +1,216 @@
+// Copyright 2022 Jigsaw Operations LLC
+//
+// 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
+//
+//     https://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 main
+
+import (
+	"bytes"
+	"encoding/base64"
+	"errors"
+	"flag"
+	"fmt"
+	"net"
+	"net/url"
+	"os"
+	"os/signal"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/Jigsaw-Code/outline-ss-server/client"
+	onet "github.com/Jigsaw-Code/outline-ss-server/net"
+	"github.com/op/go-logging"
+	"github.com/shadowsocks/go-shadowsocks2/socks"
+	"golang.org/x/crypto/ssh/terminal"
+)
+
+var logger *logging.Logger
+
+func init() {
+	var prefix = "%{level:.1s}%{time:2006-01-02T15:04:05.000Z07:00} %{pid} %{shortfile}]"
+	if terminal.IsTerminal(int(os.Stderr.Fd())) {
+		// Add color only if the output is the terminal
+		prefix = strings.Join([]string{"%{color}", prefix, "%{color:reset}"}, "")
+	}
+	logging.SetFormatter(logging.MustStringFormatter(strings.Join([]string{prefix, " %{message}"}, "")))
+	logging.SetBackend(logging.NewLogBackend(os.Stderr, "", 0))
+	logger = logging.MustGetLogger("")
+}
+
+type serverConfig struct {
+	host   string
+	port   int
+	cipher string
+	secret string
+}
+
+func parseKey(k string) (serverConfig, error) {
+	u, err := url.Parse(k)
+	if err != nil {
+		return serverConfig{}, err
+	}
+
+	port, err := strconv.Atoi(u.Port())
+	if err != nil {
+		return serverConfig{}, fmt.Errorf("invalid port: %v", err)
+	}
+
+	secret := u.User.String()
+	if !strings.Contains(secret, ":") {
+		b, err := base64.StdEncoding.DecodeString(secret)
+		if err != nil {
+			b, err = base64.RawStdEncoding.DecodeString(u.User.String())
+			if err != nil {
+				return serverConfig{}, fmt.Errorf("invalid password in key: %v", err)
+			}
+		}
+		secret = string(bytes.TrimSpace(b))
+	}
+	p := strings.Split(secret, ":")
+	if len(p) != 2 {
+		return serverConfig{}, fmt.Errorf("invalid password in key")
+	}
+
+	return serverConfig{
+		host:   u.Hostname(),
+		port:   port,
+		cipher: p[0],
+		secret: p[1],
+	}, nil
+}
+
+func resolveHostPort(addr string) (string, error) {
+	host, port, err := net.SplitHostPort(addr)
+	if err != nil {
+		return "", err
+	}
+	ip, err := net.ResolveIPAddr("ip", host)
+	if err != nil {
+		return "", fmt.Errorf("resolving hostname failed: %v", err)
+	}
+	return net.JoinHostPort(ip.String(), port), err
+}
+
+type SocksSSClient struct {
+	config   serverConfig
+	listener *net.TCPListener
+}
+
+// RunSocksSSClient starts a SOCKS server which proxies connections to the specified shadowsocks server.
+func RunSocksSSClient(bindAddr string, listenPort int, config serverConfig) (*SocksSSClient, error) {
+	listener, err := net.ListenTCP("tcp", &net.TCPAddr{IP: net.ParseIP(bindAddr), Port: listenPort})
+	if err != nil {
+		return nil, fmt.Errorf("listenTCP failed: %v", err)
+	}
+	logger.Infof("Listenting at %v", listener.Addr())
+
+	d, err := client.NewClient(config.host, config.port, config.secret, config.cipher)
+	if err != nil {
+		return nil, fmt.Errorf("failed connecting to server: %v", err)
+	}
+
+	go func() {
+		for {
+			clientConn, err := listener.AcceptTCP()
+			if err != nil {
+				if errors.Is(err, net.ErrClosed) {
+					logger.Info("SOCKS listener closed")
+				} else {
+					logger.Errorf("Accepting SOCKS connection failed: %v\n", err)
+				}
+				break
+			}
+			go func() {
+				defer clientConn.Close()
+
+				tgtAddr, err := socks.Handshake(clientConn)
+				if err != nil {
+					logger.Errorf("SOCKS handshake failed: %v", err)
+					return
+				}
+				addr, err := resolveHostPort(tgtAddr.String())
+				if err != nil {
+					logger.Errorf("Failed to resolve target address: %v", err)
+					return
+				}
+
+				logger.Debugf("Opening connection for %s", addr)
+				targetConn, err := d.DialTCP(nil, addr)
+				if err != nil {
+					logger.Errorf("Failed to dial: %v", err)
+					return
+				}
+				defer targetConn.Close()
+				_, _, err = onet.Relay(clientConn, targetConn)
+				if err != nil {
+					logger.Errorf("Relay failed: %v", err)
+					return
+				}
+				logger.Debugf("Connection closed %s", addr)
+			}()
+		}
+	}()
+	return &SocksSSClient{listener: listener}, nil
+}
+
+// ListenAddr returns the listening address used by the SOCKS server
+func (s *SocksSSClient) ListenAddr() net.Addr {
+	return s.listener.Addr()
+}
+
+// Stop stops the SOCKS server
+func (s *SocksSSClient) Stop() error {
+	return s.listener.Close()
+}
+
+func main() {
+	var flags struct {
+		BindAddr   string
+		ListenPort int
+		ServerKey  string
+		Verbose    bool
+	}
+
+	flag.StringVar(&flags.BindAddr, "bind", "127.0.0.1", "")
+	flag.IntVar(&flags.ListenPort, "port", 1080, "")
+	flag.StringVar(&flags.ServerKey, "key", "", "")
+	flag.BoolVar(&flags.Verbose, "verbose", false, "Enables verbose logging output")
+
+	flag.Parse()
+
+	if flags.Verbose {
+		logging.SetLevel(logging.DEBUG, "")
+	} else {
+		logging.SetLevel(logging.INFO, "")
+	}
+
+	if flags.ServerKey == "" {
+		flag.Usage()
+		return
+	}
+
+	sc, err := parseKey(flags.ServerKey)
+	if err != nil {
+		logger.Fatalf("Invalid key: %v", err)
+	}
+
+	_, err = RunSocksSSClient(flags.BindAddr, flags.ListenPort, sc)
+	if err != nil {
+		logger.Fatalf("Failed running client: %v", err)
+	}
+
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+	<-sigCh
+}