Deep copy dispatcher views.

When VectorisedViews were passed up the stack from packet_dispatchers, we were
passing a sub-slice of the dispatcher's views fields. The dispatchers then
immediately set those views to nil.

This wasn't caught before because every implementer copied the data in these
views before returning.

PiperOrigin-RevId: 277615351

2 files changed, 9 insertions, 5 deletions

diff --git a/pkg/tcpip/link/fdbased/endpoint_test.go b/pkg/tcpip/link/fdbased/endpoint_test.go
index 59378b96c..e7c05ca4f 100644
--- a/pkg/tcpip/link/fdbased/endpoint_test.go
+++ b/pkg/tcpip/link/fdbased/endpoint_test.go
@@ -45,7 +45,7 @@ const (
 type packetInfo struct {
 	raddr      tcpip.LinkAddress
 	proto      tcpip.NetworkProtocolNumber
-	contents   buffer.View
+	contents   buffer.VectorisedView
 	linkHeader buffer.View
 }
 
@@ -94,7 +94,7 @@ func (c *context) cleanup() {
 }
 
 func (c *context) DeliverNetworkPacket(linkEP stack.LinkEndpoint, remote tcpip.LinkAddress, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView, linkHeader buffer.View) {
-	c.ch <- packetInfo{remote, protocol, vv.ToView(), linkHeader}
+	c.ch <- packetInfo{remote, protocol, vv, linkHeader}
 }
 
 func TestNoEthernetProperties(t *testing.T) {
@@ -319,13 +319,17 @@ func TestDeliverPacket(t *testing.T) {
 					want := packetInfo{
 						raddr:      raddr,
 						proto:      proto,
-						contents:   b,
+						contents:   buffer.View(b).ToVectorisedView(),
 						linkHeader: buffer.View(hdr),
 					}
 					if !eth {
 						want.proto = header.IPv4ProtocolNumber
 						want.raddr = ""
 					}
+					// want.contents will be a single view,
+					// so make pi do the same for the
+					// DeepEqual check.
+					pi.contents = pi.contents.ToView().ToVectorisedView()
 					if !reflect.DeepEqual(want, pi) {
 						t.Fatalf("Unexpected received packet: %+v, want %+v", pi, want)
 					}
diff --git a/pkg/tcpip/link/fdbased/packet_dispatchers.go b/pkg/tcpip/link/fdbased/packet_dispatchers.go
index 12168a1dc..3331b6453 100644
--- a/pkg/tcpip/link/fdbased/packet_dispatchers.go
+++ b/pkg/tcpip/link/fdbased/packet_dispatchers.go
@@ -139,7 +139,7 @@ func (d *readVDispatcher) dispatch() (bool, *tcpip.Error) {
 	}
 
 	used := d.capViews(n, BufConfig)
-	vv := buffer.NewVectorisedView(n, d.views[:used])
+	vv := buffer.NewVectorisedView(n, append([]buffer.View(nil), d.views[:used]...))
 	vv.TrimFront(d.e.hdrSize)
 
 	d.e.dispatcher.DeliverNetworkPacket(d.e, remote, local, p, vv, buffer.View(eth))
@@ -293,7 +293,7 @@ func (d *recvMMsgDispatcher) dispatch() (bool, *tcpip.Error) {
 		}
 
 		used := d.capViews(k, int(n), BufConfig)
-		vv := buffer.NewVectorisedView(int(n), d.views[k][:used])
+		vv := buffer.NewVectorisedView(int(n), append([]buffer.View(nil), d.views[k][:used]...))
 		vv.TrimFront(d.e.hdrSize)
 		d.e.dispatcher.DeliverNetworkPacket(d.e, remote, local, p, vv, buffer.View(eth))