Pass PacketBuffer as pointer.

Historically we've been passing PacketBuffer by shallow copying through out
the stack. Right now, this is only correct as the caller would not use
PacketBuffer after passing into the next layer in netstack.

With new buffer management effort in gVisor/netstack, PacketBuffer will
own a Buffer (to be added). Internally, both PacketBuffer and Buffer may
have pointers and shallow copying shouldn't be used.

Updates #2404.

PiperOrigin-RevId: 314610879

4 files changed, 10 insertions, 10 deletions

diff --git a/pkg/tcpip/link/fdbased/endpoint.go b/pkg/tcpip/link/fdbased/endpoint.go
index 5ee508d48..f34082e1a 100644
--- a/pkg/tcpip/link/fdbased/endpoint.go
+++ b/pkg/tcpip/link/fdbased/endpoint.go
@@ -387,7 +387,7 @@ const (
 
 // WritePacket writes outbound packets to the file descriptor. If it is not
 // currently writable, the packet is dropped.
-func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) *tcpip.Error {
+func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
 	if e.hdrSize > 0 {
 		// Add ethernet header if needed.
 		eth := header.Ethernet(pkt.Header.Prepend(header.EthernetMinimumSize))
@@ -641,7 +641,7 @@ func (e *InjectableEndpoint) Attach(dispatcher stack.NetworkDispatcher) {
 }
 
 // InjectInbound injects an inbound packet.
-func (e *InjectableEndpoint) InjectInbound(protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) {
+func (e *InjectableEndpoint) InjectInbound(protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
 	e.dispatcher.DeliverNetworkPacket("" /* remote */, "" /* local */, protocol, pkt)
 }
 
diff --git a/pkg/tcpip/link/fdbased/endpoint_test.go b/pkg/tcpip/link/fdbased/endpoint_test.go
index 6f41a71a8..eaee7e5d7 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 stack.PacketBuffer
+	contents *stack.PacketBuffer
 }
 
 type context struct {
@@ -103,7 +103,7 @@ func (c *context) cleanup() {
 	}
 }
 
-func (c *context) DeliverNetworkPacket(remote tcpip.LinkAddress, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt stack.PacketBuffer) {
+func (c *context) DeliverNetworkPacket(remote tcpip.LinkAddress, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
 	c.ch <- packetInfo{remote, protocol, pkt}
 }
 
@@ -179,7 +179,7 @@ func testWritePacket(t *testing.T, plen int, eth bool, gsoMaxSize uint32, hash u
 			L3HdrLen:   header.IPv4MaximumHeaderSize,
 		}
 	}
-	if err := c.ep.WritePacket(r, gso, proto, stack.PacketBuffer{
+	if err := c.ep.WritePacket(r, gso, proto, &stack.PacketBuffer{
 		Header: hdr,
 		Data:   payload.ToVectorisedView(),
 		Hash:   hash,
@@ -295,7 +295,7 @@ func TestPreserveSrcAddress(t *testing.T) {
 	// WritePacket panics given a prependable with anything less than
 	// the minimum size of the ethernet header.
 	hdr := buffer.NewPrependable(header.EthernetMinimumSize)
-	if err := c.ep.WritePacket(r, nil /* gso */, proto, stack.PacketBuffer{
+	if err := c.ep.WritePacket(r, nil /* gso */, proto, &stack.PacketBuffer{
 		Header: hdr,
 		Data:   buffer.VectorisedView{},
 	}); err != nil {
@@ -358,7 +358,7 @@ func TestDeliverPacket(t *testing.T) {
 					want := packetInfo{
 						raddr: raddr,
 						proto: proto,
-						contents: stack.PacketBuffer{
+						contents: &stack.PacketBuffer{
 							Data:       buffer.View(b).ToVectorisedView(),
 							LinkHeader: buffer.View(hdr),
 						},
diff --git a/pkg/tcpip/link/fdbased/mmap.go b/pkg/tcpip/link/fdbased/mmap.go
index ca4229ed6..2dfd29aa9 100644
--- a/pkg/tcpip/link/fdbased/mmap.go
+++ b/pkg/tcpip/link/fdbased/mmap.go
@@ -191,7 +191,7 @@ func (d *packetMMapDispatcher) dispatch() (bool, *tcpip.Error) {
 	}
 
 	pkt = pkt[d.e.hdrSize:]
-	d.e.dispatcher.DeliverNetworkPacket(remote, local, p, stack.PacketBuffer{
+	d.e.dispatcher.DeliverNetworkPacket(remote, local, p, &stack.PacketBuffer{
 		Data:       buffer.View(pkt).ToVectorisedView(),
 		LinkHeader: buffer.View(eth),
 	})
diff --git a/pkg/tcpip/link/fdbased/packet_dispatchers.go b/pkg/tcpip/link/fdbased/packet_dispatchers.go
index 26c96a655..f04738cfb 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)
-	pkt := stack.PacketBuffer{
+	pkt := &stack.PacketBuffer{
 		Data:       buffer.NewVectorisedView(n, append([]buffer.View(nil), d.views[:used]...)),
 		LinkHeader: buffer.View(eth),
 	}
@@ -296,7 +296,7 @@ func (d *recvMMsgDispatcher) dispatch() (bool, *tcpip.Error) {
 		}
 
 		used := d.capViews(k, int(n), BufConfig)
-		pkt := stack.PacketBuffer{
+		pkt := &stack.PacketBuffer{
 			Data:       buffer.NewVectorisedView(int(n), append([]buffer.View(nil), d.views[k][:used]...)),
 			LinkHeader: buffer.View(eth),
 		}