add tcp redirect

pkg/handler/redirect/handler.go

@@ -0,0 +1,114 @@
+package redirect
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/go-gost/gost/pkg/bypass"
+	"github.com/go-gost/gost/pkg/chain"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+	md "github.com/go-gost/gost/pkg/metadata"
+	"github.com/go-gost/gost/pkg/registry"
+)
+
+func init() {
+	registry.RegisterHandler("red", NewHandler)
+	registry.RegisterHandler("redir", NewHandler)
+	registry.RegisterHandler("redirect", NewHandler)
+}
+
+type redirectHandler struct {
+	chain  *chain.Chain
+	bypass bypass.Bypass
+	logger logger.Logger
+	md     metadata
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := &handler.Options{}
+	for _, opt := range opts {
+		opt(options)
+	}
+
+	return &redirectHandler{
+		bypass: options.Bypass,
+		logger: options.Logger,
+	}
+}
+
+func (h *redirectHandler) Init(md md.Metadata) (err error) {
+	return h.parseMetadata(md)
+}
+
+// WithChain implements chain.Chainable interface
+func (h *redirectHandler) WithChain(chain *chain.Chain) {
+	h.chain = chain
+}
+
+func (h *redirectHandler) Handle(ctx context.Context, conn net.Conn) {
+	start := time.Now()
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+	})
+
+	h.logger.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		h.logger.WithFields(map[string]interface{}{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	network := "tcp"
+	var dstAddr net.Addr
+	var err error
+
+	if _, ok := conn.(net.PacketConn); ok {
+		network = "udp"
+		dstAddr = conn.LocalAddr()
+	}
+
+	if network == "tcp" {
+		dstAddr, conn, err = h.getOriginalDstAddr(conn)
+		if err != nil {
+			h.logger.Error(err)
+			return
+		}
+	}
+	defer conn.Close()
+
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"dst": fmt.Sprintf("%s/%s", dstAddr, network),
+	})
+
+	h.logger.Infof("%s >> %s", conn.RemoteAddr(), dstAddr)
+
+	if h.bypass != nil && h.bypass.Contains(dstAddr.String()) {
+		h.logger.Info("bypass: ", dstAddr)
+		return
+	}
+
+	r := (&chain.Router{}).
+		WithChain(h.chain).
+		WithRetry(h.md.retryCount).
+		WithLogger(h.logger)
+
+	cc, err := r.Dial(ctx, network, dstAddr.String())
+	if err != nil {
+		h.logger.Error(err)
+		return
+	}
+	defer cc.Close()
+
+	t := time.Now()
+	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), dstAddr)
+	handler.Transport(conn, cc)
+	h.logger.
+		WithFields(map[string]interface{}{
+			"duration": time.Since(t),
+		}).
+		Infof("%s >-< %s", conn.RemoteAddr(), dstAddr)
+}