initial commit

handler/relay/forward.go

@@ -0,0 +1,91 @@
+package relay
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"time"
+
+	netpkg "github.com/go-gost/gost/v3/pkg/common/net"
+	"github.com/go-gost/gost/v3/pkg/logger"
+	"github.com/go-gost/relay"
+)
+
+func (h *relayHandler) handleForward(ctx context.Context, conn net.Conn, network string, log logger.Logger) error {
+	resp := relay.Response{
+		Version: relay.Version1,
+		Status:  relay.StatusOK,
+	}
+	target := h.group.Next()
+	if target == nil {
+		resp.Status = relay.StatusServiceUnavailable
+		resp.WriteTo(conn)
+		err := errors.New("target not available")
+		log.Error(err)
+		return err
+	}
+
+	log = log.WithFields(map[string]any{
+		"dst": fmt.Sprintf("%s/%s", target.Addr, network),
+		"cmd": "forward",
+	})
+
+	log.Infof("%s >> %s", conn.RemoteAddr(), target.Addr)
+
+	cc, err := h.router.Dial(ctx, network, target.Addr)
+	if err != nil {
+		// TODO: the router itself may be failed due to the failed node in the router,
+		// the dead marker may be a wrong operation.
+		target.Marker.Mark()
+
+		resp.Status = relay.StatusHostUnreachable
+		resp.WriteTo(conn)
+		log.Error(err)
+
+		return err
+	}
+	defer cc.Close()
+	target.Marker.Reset()
+
+	if h.md.noDelay {
+		if _, err := resp.WriteTo(conn); err != nil {
+			log.Error(err)
+			return err
+		}
+	}
+
+	switch network {
+	case "udp", "udp4", "udp6":
+		rc := &udpConn{
+			Conn: conn,
+		}
+		if !h.md.noDelay {
+			// cache the header
+			if _, err := resp.WriteTo(&rc.wbuf); err != nil {
+				return err
+			}
+		}
+		conn = rc
+	default:
+		rc := &tcpConn{
+			Conn: conn,
+		}
+		if !h.md.noDelay {
+			// cache the header
+			if _, err := resp.WriteTo(&rc.wbuf); err != nil {
+				return err
+			}
+		}
+		conn = rc
+	}
+
+	t := time.Now()
+	log.Infof("%s <-> %s", conn.RemoteAddr(), target.Addr)
+	netpkg.Transport(conn, cc)
+	log.WithFields(map[string]any{
+		"duration": time.Since(t),
+	}).Infof("%s >-< %s", conn.RemoteAddr(), target.Addr)
+
+	return nil
+}