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

1 files changed, 2 insertions, 7 deletions

diff --git a/pkg/tcpip/network/ipv4/ipv4.go b/pkg/tcpip/network/ipv4/ipv4.go
index e589d923d..254d66147 100644
--- a/pkg/tcpip/network/ipv4/ipv4.go
+++ b/pkg/tcpip/network/ipv4/ipv4.go
@@ -12,12 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// Package ipv4 contains the implementation of the ipv4 network protocol. To use
-// it in the networking stack, this package must be added to the project, and
-// activated on the stack by passing ipv4.NewProtocol() as one of the network
-// protocols when calling stack.New(). Then endpoints can be created by passing
-// ipv4.ProtocolNumber as the network protocol number when calling
-// Stack.NewEndpoint().
+// Package ipv4 contains the implementation of the ipv4 network protocol.
 package ipv4
 
 import (
@@ -584,7 +579,7 @@ func hashRoute(r *stack.Route, protocol tcpip.TransportProtocolNumber, hashIV ui
 }
 
 // NewProtocol returns an IPv4 network protocol.
-func NewProtocol() stack.NetworkProtocol {
+func NewProtocol(*stack.Stack) stack.NetworkProtocol {
 	ids := make([]uint32, buckets)
 
 	// Randomly initialize hashIV and the ids.