package echoserver import ( "fmt" "net" "strings" fnet "github.com/fatedier/frp/utils/net" ) type ServerType string const ( TCP ServerType = "tcp" UDP ServerType = "udp" Unix ServerType = "unix" ) type Options struct { Type ServerType BindAddr string BindPort int32 RepeatNum int SpecifiedResponse string } type Server struct { opt Options l net.Listener } func New(opt Options) *Server { if opt.Type == "" { opt.Type = TCP } if opt.BindAddr == "" { opt.BindAddr = "127.0.0.1" } if opt.RepeatNum <= 0 { opt.RepeatNum = 1 } return &Server{ opt: opt, } } func (s *Server) GetOptions() Options { return s.opt } func (s *Server) Run() error { if err := s.initListener(); err != nil { return err } go func() { for { c, err := s.l.Accept() if err != nil { return } go s.handle(c) } }() return nil } func (s *Server) Close() error { if s.l != nil { return s.l.Close() } return nil } func (s *Server) initListener() (err error) { switch s.opt.Type { case TCP: s.l, err = net.Listen("tcp", fmt.Sprintf("%s:%d", s.opt.BindAddr, s.opt.BindPort)) case UDP: s.l, err = fnet.ListenUDP(s.opt.BindAddr, int(s.opt.BindPort)) case Unix: s.l, err = net.Listen("unix", s.opt.BindAddr) default: return fmt.Errorf("unknown server type: %s", s.opt.Type) } if err != nil { return } return nil } func (s *Server) handle(c net.Conn) { defer c.Close() buf := make([]byte, 2048) for { n, err := c.Read(buf) if err != nil { return } var response string if len(s.opt.SpecifiedResponse) > 0 { response = s.opt.SpecifiedResponse } else { response = strings.Repeat(string(buf[:n]), s.opt.RepeatNum) } c.Write([]byte(response)) } }