Support creating protocol instances with Stack ref

Network or transport protocols may want to reach the stack. Support this
by letting the stack create the protocol instances so it can pass a
reference to itself at protocol creation time.

Note, protocols do not yet use the stack in this CL but later CLs will
make use of the stack from protocols.

PiperOrigin-RevId: 334260210

2 files changed, 14 insertions, 20 deletions

diff --git a/pkg/tcpip/transport/udp/protocol.go b/pkg/tcpip/transport/udp/protocol.go
index a1d0f49d9..e6fc23258 100644
--- a/pkg/tcpip/transport/udp/protocol.go
+++ b/pkg/tcpip/transport/udp/protocol.go
@@ -12,12 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package udp contains the implementation of the UDP transport protocol. To use
-// it in the networking stack, this package must be added to the project, and
-// activated on the stack by passing udp.NewProtocol() as one of the
-// transport protocols when calling stack.New(). Then endpoints can be created
-// by passing udp.ProtocolNumber as the transport protocol number when calling
-// Stack.NewEndpoint().
+// Package udp contains the implementation of the UDP transport protocol.
 package udp
 
 import (
@@ -119,6 +114,6 @@ func (*protocol) Parse(pkt *stack.PacketBuffer) bool {
 }
 
 // NewProtocol returns a UDP transport protocol.
-func NewProtocol() stack.TransportProtocol {
+func NewProtocol(*stack.Stack) stack.TransportProtocol {
 	return &protocol{}
 }
diff --git a/pkg/tcpip/transport/udp/udp_test.go b/pkg/tcpip/transport/udp/udp_test.go
index 6813d57aa..0556ef879 100644
--- a/pkg/tcpip/transport/udp/udp_test.go
+++ b/pkg/tcpip/transport/udp/udp_test.go
@@ -294,8 +294,8 @@ type testContext struct {
 func newDualTestContext(t *testing.T, mtu uint32) *testContext {
 	t.Helper()
 	return newDualTestContextWithOptions(t, mtu, stack.Options{
-		NetworkProtocols:   []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
-		TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()},
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
 	})
 }
 
@@ -532,8 +532,8 @@ func newMinPayload(minSize int) []byte {
 
 func TestBindToDeviceOption(t *testing.T) {
 	s := stack.New(stack.Options{
-		NetworkProtocols:   []stack.NetworkProtocol{ipv4.NewProtocol()},
-		TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()}})
+		NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol},
+		TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol}})
 
 	ep, err := s.NewEndpoint(udp.ProtocolNumber, ipv4.ProtocolNumber, &waiter.Queue{})
 	if err != nil {
@@ -807,8 +807,8 @@ func TestV4ReadSelfSource(t *testing.T) {
 	} {
 		t.Run(tt.name, func(t *testing.T) {
 			c := newDualTestContextWithOptions(t, defaultMTU, stack.Options{
-				NetworkProtocols:   []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
-				TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()},
+				NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+				TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
 				HandleLocal:        tt.handleLocal,
 			})
 			defer c.cleanup()
@@ -1485,13 +1485,13 @@ func TestTTL(t *testing.T) {
 			} else {
 				var p stack.NetworkProtocol
 				if flow.isV4() {
-					p = ipv4.NewProtocol()
+					p = ipv4.NewProtocol(nil)
 				} else {
-					p = ipv6.NewProtocol()
+					p = ipv6.NewProtocol(nil)
 				}
 				ep := p.NewEndpoint(0, nil, nil, nil, nil, stack.New(stack.Options{
-					NetworkProtocols:   []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
-					TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()},
+					NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+					TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
 				}))
 				wantTTL = ep.DefaultTTL()
 				ep.Close()
@@ -2345,9 +2345,8 @@ func TestOutgoingSubnetBroadcast(t *testing.T) {
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
 			s := stack.New(stack.Options{
-				NetworkProtocols: []stack.NetworkProtocol{ipv4.NewProtocol(), ipv6.NewProtocol()},
-
-				TransportProtocols: []stack.TransportProtocol{udp.NewProtocol()},
+				NetworkProtocols:   []stack.NetworkProtocolFactory{ipv4.NewProtocol, ipv6.NewProtocol},
+				TransportProtocols: []stack.TransportProtocolFactory{udp.NewProtocol},
 			})
 			e := channel.New(0, defaultMTU, "")
 			if err := s.CreateNIC(nicID1, e); err != nil {