/
server.go
213 lines (171 loc) · 4.21 KB
/
server.go
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package main
import (
"encoding/binary"
"errors"
"net"
"github.com/google/uuid"
"github.com/rs/zerolog/log"
)
type (
db = Map[string, net.Conn]
)
type Server struct {
addr *net.TCPAddr
connStore *db
author *Authenticator
}
func NewServer(port int, secret string) *Server {
addr := &net.TCPAddr{
IP: nil,
Port: port,
}
srv := &Server{
addr: addr,
connStore: new(db),
}
if len(secret) > 0 {
srv.author = NewAuthenticator(secret)
}
return srv
}
func (svr *Server) Start() error {
ln, err := net.ListenTCP("tcp", svr.addr)
if err != nil {
log.Error().Err(err).Msg("server listen error")
return err
}
log.Info().Str("addr", ln.Addr().String()).Msg("server listen success.")
for {
stream, err := ln.AcceptTCP()
if err != nil {
log.Error().Err(err).Msg("accept fail.")
break
}
remote := stream.RemoteAddr().String()
log.Info().Str("remote", remote).Msg("incoming connection.")
Go("handle", func() {
defer func() {
if stream != nil {
_ = stream.Close()
}
log.Info().Str("remote", remote).Msg("client exit.")
}()
svr.handle(stream)
})
}
return nil
}
func (svr *Server) handle(stream *net.TCPConn) {
// 鉴权
if svr.author != nil {
log.Debug().Msg("handshake start")
if err := svr.handshake(stream); err != nil {
log.Error().Err(err).Msg("handshake fail")
packet := failPacket(err)
_, _ = stream.Write(packet)
return
}
}
log.Debug().Msg("handshake success")
var newType ttype
if err := binary.Read(stream, binary.BigEndian, &newType); err != nil {
log.Error().Err(err).Msg("read fail")
return
}
log.Debug().Uint8("ttype", uint8(newType)).Msg("message info")
switch newType {
case hello:
if err := svr.handleHello(stream); err != nil {
log.Error().Err(err).Msg("client handShake error")
}
case transfer:
if err := svr.handleTransfer(stream); err != nil {
log.Error().Err(err).Msg("client transfer error")
}
case auth:
log.Error().Msg("unexpect auth message")
packet := failPacket(ErrNoAuthRequred)
_, _ = stream.Write(packet)
return
default:
panic("unhandled default case")
}
}
func (svr *Server) handshake(stream *net.TCPConn) error {
id := uuid.New()
log.Debug().Str("id", id.String()).Msg("handshake start,write to client")
// 1. send
if _, err := stream.Write(challengePacket(id)); err != nil {
return err
}
// 2. wait client
tag, err := parseAuthPacket(stream)
if err != nil {
return err
}
// 3. auth
if verify := svr.author.Verify(id, tag); !verify {
return ErrInvalidSecret
}
return nil
}
func (svr *Server) handleHello(stream *net.TCPConn) error {
port, err := parseHelloPacket(stream)
if err != nil {
log.Error().Err(err).Msg("read hello message error")
return err
}
addr := &net.TCPAddr{
IP: nil,
Port: int(port),
}
ln, err := net.ListenTCP("tcp", addr)
if err != nil {
log.Error().Err(err).Str("addr", addr.String()).Msg("listen error")
return err
}
realPort := ln.Addr().(*net.TCPAddr).Port
packet := helloPacket(uint16(realPort))
log.Info().Int("port", realPort).Str("remote", stream.RemoteAddr().String()).Msg("mapping port.")
if _, err := stream.Write(packet); err != nil {
log.Error().Err(err).Msg("write hello message error")
return err
}
for {
incoming, err := ln.AcceptTCP()
if err != nil {
log.Error().Err(err).Msg("accept error")
break
}
log.Debug().Msg("incoming request")
id := uuid.New()
svr.connStore.Store(id.String(), incoming)
packet := transferOrConnectPacket(id, connect)
if _, err := stream.Write(packet); err != nil {
log.Error().Err(err).Msg("write error")
}
}
return nil
}
func (svr *Server) handleTransfer(stream *net.TCPConn) error {
log.Debug().Msg("handle forward")
uid, err := parseTransferOrConnectPacket(stream)
if err != nil {
return err
}
session, ok := svr.connStore.Load(uid.String())
if !ok {
return errors.New("not exist:" + uid.String())
}
inCount, outCount, errs := relay(session, stream)
if errs != nil {
log.Error().Any("errors", errs).Msg("relay fail")
return nil
}
log.Info().Int64("in", inCount).Int64("out", outCount).Msg("forward success.")
return nil
}
func StartServer(port int, secret string) error {
server := NewServer(port, secret)
return server.Start()
}