Migrate to PacketHeader API for PacketBuffer.

Formerly, when a packet is constructed or parsed, all headers are set by the
client code. This almost always involved prepending to pk.Header buffer or
trimming pk.Data portion. This is known to prone to bugs, due to the complexity
and number of the invariants assumed across netstack to maintain.

In the new PacketHeader API, client will call Push()/Consume() method to
construct/parse an outgoing/incoming packet. All invariants, such as slicing
and trimming, are maintained by the API itself.

NewPacketBuffer() is introduced to create new PacketBuffer. Zero value is no
longer valid.

PacketBuffer now assumes the packet is a concatenation of following portions:
* LinkHeader
* NetworkHeader
* TransportHeader
* Data
Any of them could be empty, or zero-length.

PiperOrigin-RevId: 326507688

1 files changed, 12 insertions, 10 deletions

diff --git a/pkg/tcpip/stack/ndp_test.go b/pkg/tcpip/stack/ndp_test.go
index 5d286ccbc..21bf53010 100644
--- a/pkg/tcpip/stack/ndp_test.go
+++ b/pkg/tcpip/stack/ndp_test.go
@@ -541,7 +541,7 @@ func TestDADResolve(t *testing.T) {
 				// As per RFC 4861 section 4.3, a possible option is the Source Link
 				// Layer option, but this option MUST NOT be included when the source
 				// address of the packet is the unspecified address.
-				checker.IPv6(t, p.Pkt.Header.View(),
+				checker.IPv6(t, stack.PayloadSince(p.Pkt.NetworkHeader()),
 					checker.SrcAddr(header.IPv6Any),
 					checker.DstAddr(snmc),
 					checker.TTL(header.NDPHopLimit),
@@ -550,8 +550,8 @@ func TestDADResolve(t *testing.T) {
 						checker.NDPNSOptions(nil),
 					))
 
-				if l, want := p.Pkt.Header.AvailableLength(), int(test.linkHeaderLen); l != want {
-					t.Errorf("got p.Pkt.Header.AvailableLength() = %d; want = %d", l, want)
+				if l, want := p.Pkt.AvailableHeaderBytes(), int(test.linkHeaderLen); l != want {
+					t.Errorf("got p.Pkt.AvailableHeaderBytes() = %d; want = %d", l, want)
 				}
 			}
 		})
@@ -667,9 +667,10 @@ func TestDADFail(t *testing.T) {
 			// Receive a packet to simulate multiple nodes owning or
 			// attempting to own the same address.
 			hdr := test.makeBuf(addr1)
-			e.InjectInbound(header.IPv6ProtocolNumber, &stack.PacketBuffer{
+			pkt := stack.NewPacketBuffer(stack.PacketBufferOptions{
 				Data: hdr.View().ToVectorisedView(),
 			})
+			e.InjectInbound(header.IPv6ProtocolNumber, pkt)
 
 			stat := test.getStat(s.Stats().ICMP.V6PacketsReceived)
 			if got := stat.Value(); got != 1 {
@@ -1024,7 +1025,9 @@ func raBufWithOptsAndDHCPv6(ip tcpip.Address, rl uint16, managedAddress, otherCo
 		DstAddr:       header.IPv6AllNodesMulticastAddress,
 	})
 
-	return &stack.PacketBuffer{Data: hdr.View().ToVectorisedView()}
+	return stack.NewPacketBuffer(stack.PacketBufferOptions{
+		Data: hdr.View().ToVectorisedView(),
+	})
 }
 
 // raBufWithOpts returns a valid NDP Router Advertisement with options.
@@ -5134,16 +5137,15 @@ func TestRouterSolicitation(t *testing.T) {
 						t.Errorf("got remote link address = %s, want = %s", p.Route.RemoteLinkAddress, want)
 					}
 
-					checker.IPv6(t,
-						p.Pkt.Header.View(),
+					checker.IPv6(t, stack.PayloadSince(p.Pkt.NetworkHeader()),
 						checker.SrcAddr(test.expectedSrcAddr),
 						checker.DstAddr(header.IPv6AllRoutersMulticastAddress),
 						checker.TTL(header.NDPHopLimit),
 						checker.NDPRS(checker.NDPRSOptions(test.expectedNDPOpts)),
 					)
 
-					if l, want := p.Pkt.Header.AvailableLength(), int(test.linkHeaderLen); l != want {
-						t.Errorf("got p.Pkt.Header.AvailableLength() = %d; want = %d", l, want)
+					if l, want := p.Pkt.AvailableHeaderBytes(), int(test.linkHeaderLen); l != want {
+						t.Errorf("got p.Pkt.AvailableHeaderBytes() = %d; want = %d", l, want)
 					}
 				}
 				waitForNothing := func(timeout time.Duration) {
@@ -5288,7 +5290,7 @@ func TestStopStartSolicitingRouters(t *testing.T) {
 				if p.Proto != header.IPv6ProtocolNumber {
 					t.Fatalf("got Proto = %d, want = %d", p.Proto, header.IPv6ProtocolNumber)
 				}
-				checker.IPv6(t, p.Pkt.Header.View(),
+				checker.IPv6(t, stack.PayloadSince(p.Pkt.NetworkHeader()),
 					checker.SrcAddr(header.IPv6Any),
 					checker.DstAddr(header.IPv6AllRoutersMulticastAddress),
 					checker.TTL(header.NDPHopLimit),