go-tunnel/control/control.go

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2020-10-21 18:00:15 +02:00
package control
import (
"context"
"encoding/json"
"net"
"time"
"github.com/pkg/errors"
"github.com/xtaci/smux"
"gitlab.com/wpetit/goweb/logger"
)
type Control struct {
encoder *json.Encoder
decoder *json.Decoder
stream *smux.Stream
sess *smux.Session
}
func (c *Control) AuthRequest(credentials interface{}) (bool, error) {
req := NewMessage(TypeAuthRequest, &AuthRequestPayload{
Credentials: credentials,
})
res := NewMessage(TypeAuthResponse, nil)
if err := c.reqRes(req, res); err != nil {
return false, errors.WithStack(err)
}
authResPayload, ok := res.Payload.(*AuthResponsePayload)
if !ok {
return false, errors.WithStack(ErrUnexpectedMessage)
}
return authResPayload.Success, nil
}
type CloseStream func()
func (c *Control) Proxy(ctx context.Context, network, address string) (net.Conn, error) {
var (
stream *smux.Stream
err error
)
req := NewMessage(TypeProxyRequest, &ProxyRequestPayload{
Network: network,
Address: address,
})
ctx = logger.With(ctx, logger.F("network", network), logger.F("address", address))
logger.Debug(ctx, "proxying")
if err := c.Write(req); err != nil {
return nil, errors.WithStack(err)
}
logger.Debug(ctx, "opening stream")
stream, err = c.sess.AcceptStream()
if err != nil {
return nil, errors.WithStack(err)
}
return stream, nil
}
func (c *Control) Listen(ctx context.Context, handlers Handlers) error {
for {
logger.Debug(ctx, "reading next message")
req, err := c.Read()
if err != nil {
return errors.WithStack(err)
}
go func() {
subCtx := logger.With(ctx, logger.F("messageType", req.Type))
handler, exists := handlers[req.Type]
if !exists {
logger.Error(subCtx, "no message handler registered")
return
}
res, err := handler(subCtx, req)
if err != nil {
logger.Error(subCtx, "error while handling message", logger.E(err))
return
}
if res == nil {
return
}
if err := c.Write(res); err != nil {
logger.Error(subCtx, "error while write message response", logger.E(err))
return
}
}()
}
}
func (c *Control) Read() (*Message, error) {
message := &Message{}
if err := c.read(message); err != nil {
return nil, errors.WithStack(err)
}
return message, nil
}
func (c *Control) Write(m *Message) error {
if err := c.write(m); err != nil {
return errors.WithStack(err)
}
return nil
}
func (c *Control) reqRes(req *Message, res *Message) error {
if err := c.write(req); err != nil {
return errors.WithStack(err)
}
if err := c.read(res); err != nil {
return errors.WithStack(err)
}
return nil
}
func (c *Control) read(m *Message) error {
if err := c.decoder.Decode(m); err != nil {
return errors.WithStack(err)
}
return nil
}
func (c *Control) write(m *Message) error {
if err := c.stream.SetWriteDeadline(time.Now().Add(time.Second)); err != nil {
return errors.WithStack(err)
}
if err := c.encoder.Encode(m); err != nil {
return errors.WithStack(err)
}
return nil
}
func New(sess *smux.Session, controlStream *smux.Stream) *Control {
return &Control{
encoder: json.NewEncoder(controlStream),
decoder: json.NewDecoder(controlStream),
sess: sess,
stream: controlStream,
}
}