feat(forwarder): split forwarder to different file

core/pipe.go

@@ -0,0 +1,45 @@
+package core
+
+import (
+	"errors"
+	"io"
+	"log/slog"
+	"net"
+)
+
+func pipeConns(a, b net.Conn) (toA, toB int64) {
+	done := make(chan struct{}, 2)
+	var aToB, bToA int64
+
+	go func() {
+		defer func() { done <- struct{}{} }()
+		n, err := io.Copy(a, b)
+		aToB = n
+		if err != nil && !errors.Is(err, io.EOF) && !errors.Is(err, net.ErrClosed) {
+			slog.Debug("pipe copy error", "direction", "b->a", "error", err)
+		}
+		if tc, ok := a.(*net.TCPConn); ok {
+			tc.CloseWrite()
+		} else {
+			a.Close()
+		}
+	}()
+
+	go func() {
+		defer func() { done <- struct{}{} }()
+		n, err := io.Copy(b, a)
+		bToA = n
+		if err != nil && !errors.Is(err, io.EOF) && !errors.Is(err, net.ErrClosed) {
+			slog.Debug("pipe copy error", "direction", "a->b", "error", err)
+		}
+		if tc, ok := b.(*net.TCPConn); ok {
+			tc.CloseWrite()
+		} else {
+			b.Close()
+		}
+	}()
+
+	<-done
+	<-done
+	return aToB, bToA
+}