package tun2 import ( "crypto/tls" "encoding/json" "errors" "log" "net" "net/http" "net/http/httputil" "net/url" kcp "github.com/xtaci/kcp-go" "github.com/xtaci/smux" ) type Client struct { cfg *ClientConfig } type ClientConfig struct { TLSConfig *tls.Config ConnType string ServerAddr string Token string Domain string BackendURL string } func NewClient(cfg *ClientConfig) (*Client, error) { if cfg == nil { return nil, errors.New("tun2: client config needed") } c := &Client{ cfg: cfg, } return c, nil } func (c *Client) Connect() error { return c.connect(c.cfg.ServerAddr) } func (c *Client) connect(serverAddr string) error { target, err := url.Parse(c.cfg.BackendURL) if err != nil { return err } s := &http.Server{ Handler: httputil.NewSingleHostReverseProxy(target), } var conn net.Conn switch c.cfg.ConnType { case "tcp": conn, err = tls.Dial("tcp", serverAddr, c.cfg.TLSConfig) if err != nil { return err } case "kcp": kc, err := kcp.Dial(serverAddr) if err != nil { return err } defer kc.Close() serverHost, _, _ := net.SplitHostPort(serverAddr) tc := c.cfg.TLSConfig.Clone() tc.ServerName = serverHost conn = tls.Client(kc, tc) } defer conn.Close() log.Printf("tun2: connected to %s (%v)", conn.RemoteAddr(), c.cfg.ConnType) session, err := smux.Client(conn, smux.DefaultConfig()) if err != nil { return err } defer session.Close() controlStream, err := session.AcceptStream() if err != nil { return err } authData, err := json.Marshal(&Auth{ Token: c.cfg.Token, Domain: c.cfg.Domain, }) if err != nil { return err } _, err = controlStream.Write(authData) if err != nil { return err } log.Println("tun2: client set up and waiting for requests") err = s.Serve(&smuxListener{ conn: conn, session: session, }) if err != nil { return err } return nil } type smuxListener struct { conn net.Conn session *smux.Session } var ( _ net.Listener = &smuxListener{} // interface check ) func (sl *smuxListener) Accept() (net.Conn, error) { return sl.session.AcceptStream() } func (sl *smuxListener) Addr() net.Addr { return sl.conn.LocalAddr() } func (sl *smuxListener) Close() error { return sl.session.Close() }