Fix view.ToVectorisedView().

view.ToVectorisedView() now just returns an empty vectorised
view if the view is of zero length. Earlier it would return
a VectorisedView of zero length but with 1 empty view. This
has been a source of bugs as lower layers don't expect
zero length views in VectorisedViews.

VectorisedView.AppendView() now is a no-op if the view being
appended is of zero length.

Fixes #2658

PiperOrigin-RevId: 310942269

1 files changed, 6 insertions, 0 deletions

diff --git a/pkg/tcpip/buffer/view.go b/pkg/tcpip/buffer/view.go
index f01217c91..9a3c5d6c3 100644
--- a/pkg/tcpip/buffer/view.go
+++ b/pkg/tcpip/buffer/view.go
@@ -59,6 +59,9 @@ func (v *View) Reader() bytes.Reader {
 
 // ToVectorisedView returns a VectorisedView containing the receiver.
 func (v View) ToVectorisedView() VectorisedView {
+	if len(v) == 0 {
+		return VectorisedView{}
+	}
 	return NewVectorisedView(len(v), []View{v})
 }
 
@@ -229,6 +232,9 @@ func (vv *VectorisedView) Append(vv2 VectorisedView) {
 
 // AppendView appends the given view into this vectorised view.
 func (vv *VectorisedView) AppendView(v View) {
+	if len(v) == 0 {
+		return
+	}
 	vv.views = append(vv.views, v)
 	vv.size += len(v)
 }