3 files changed, 20 insertions, 42 deletions

diff --git a/pkg/tcpip/stack/packet_buffer.go b/pkg/tcpip/stack/packet_buffer.go
index bf248ef20..456b0cf80 100644
--- a/pkg/tcpip/stack/packet_buffer.go
+++ b/pkg/tcpip/stack/packet_buffer.go
@@ -425,13 +425,14 @@ func (d PacketData) PullUp(size int) (tcpipbuffer.View, bool) {
 	return d.pk.buf.PullUp(d.pk.dataOffset(), size)
 }
 
-// DeleteFront removes count from the beginning of d. It panics if count >
-// d.Size(). All backing storage references after the front of the d are
-// invalidated.
-func (d PacketData) DeleteFront(count int) {
-	if !d.pk.buf.Remove(d.pk.dataOffset(), count) {
-		panic("count > d.Size()")
+// Consume is the same as PullUp except that is additionally consumes the
+// returned bytes. Subsequent PullUp or Consume will not return these bytes.
+func (d PacketData) Consume(size int) (tcpipbuffer.View, bool) {
+	v, ok := d.PullUp(size)
+	if ok {
+		d.pk.consumed += size
 	}
+	return v, ok
 }
 
 // CapLength reduces d to at most length bytes.
diff --git a/pkg/tcpip/stack/packet_buffer_test.go b/pkg/tcpip/stack/packet_buffer_test.go
index 87b023445..c376ed1a1 100644
--- a/pkg/tcpip/stack/packet_buffer_test.go
+++ b/pkg/tcpip/stack/packet_buffer_test.go
@@ -123,32 +123,6 @@ func TestPacketHeaderPush(t *testing.T) {
 	}
 }
 
-func TestPacketBufferClone(t *testing.T) {
-	data := concatViews(makeView(20), makeView(30), makeView(40))
-	pk := NewPacketBuffer(PacketBufferOptions{
-		// Make a copy of data to make sure our truth data won't be taint by
-		// PacketBuffer.
-		Data: buffer.NewViewFromBytes(data).ToVectorisedView(),
-	})
-
-	bytesToDelete := 30
-	originalSize := data.Size()
-
-	clonedPks := []*PacketBuffer{
-		pk.Clone(),
-		pk.CloneToInbound(),
-	}
-	pk.Data().DeleteFront(bytesToDelete)
-	if got, want := pk.Data().Size(), originalSize-bytesToDelete; got != want {
-		t.Errorf("original packet was not changed: size expected = %d, got = %d", want, got)
-	}
-	for _, clonedPk := range clonedPks {
-		if got := clonedPk.Data().Size(); got != originalSize {
-			t.Errorf("cloned packet should not be modified: expected size = %d, got = %d", originalSize, got)
-		}
-	}
-}
-
 func TestPacketHeaderConsume(t *testing.T) {
 	for _, test := range []struct {
 		name      string
@@ -461,11 +435,17 @@ func TestPacketBufferData(t *testing.T) {
 				}
 			})
 
-			// DeleteFront
+			// Consume.
 			for _, n := range []int{1, len(tc.data)} {
-				t.Run(fmt.Sprintf("DeleteFront%d", n), func(t *testing.T) {
+				t.Run(fmt.Sprintf("Consume%d", n), func(t *testing.T) {
 					pkt := tc.makePkt(t)
-					pkt.Data().DeleteFront(n)
+					v, ok := pkt.Data().Consume(n)
+					if !ok {
+						t.Fatalf("Consume failed")
+					}
+					if want := []byte(tc.data)[:n]; !bytes.Equal(v, want) {
+						t.Fatalf("pkt.Data().Consume(n) = 0x%x, want 0x%x", v, want)
+					}
 
 					checkData(t, pkt, []byte(tc.data)[n:])
 				})
diff --git a/pkg/tcpip/stack/stack_test.go b/pkg/tcpip/stack/stack_test.go
index cd4137794..c23e91702 100644
--- a/pkg/tcpip/stack/stack_test.go
+++ b/pkg/tcpip/stack/stack_test.go
@@ -139,18 +139,15 @@ func (f *fakeNetworkEndpoint) HandlePacket(pkt *stack.PacketBuffer) {
 
 	// Handle control packets.
 	if netHdr[protocolNumberOffset] == uint8(fakeControlProtocol) {
-		hdr, ok := pkt.Data().PullUp(fakeNetHeaderLen)
+		hdr, ok := pkt.Data().Consume(fakeNetHeaderLen)
 		if !ok {
 			return
 		}
-		// DeleteFront invalidates slices. Make a copy before trimming.
-		nb := append([]byte(nil), hdr...)
-		pkt.Data().DeleteFront(fakeNetHeaderLen)
 		f.dispatcher.DeliverTransportError(
-			tcpip.Address(nb[srcAddrOffset:srcAddrOffset+1]),
-			tcpip.Address(nb[dstAddrOffset:dstAddrOffset+1]),
+			tcpip.Address(hdr[srcAddrOffset:srcAddrOffset+1]),
+			tcpip.Address(hdr[dstAddrOffset:dstAddrOffset+1]),
 			fakeNetNumber,
-			tcpip.TransportProtocolNumber(nb[protocolNumberOffset]),
+			tcpip.TransportProtocolNumber(hdr[protocolNumberOffset]),
 			// Nothing checks the error.
 			nil, /* transport error */
 			pkt,