1 files changed, 17 insertions, 58 deletions

diff --git a/pkg/tcpip/link/sniffer/sniffer.go b/pkg/tcpip/link/sniffer/sniffer.go
index f2e47b6a7..d9cd4e83a 100644
--- a/pkg/tcpip/link/sniffer/sniffer.go
+++ b/pkg/tcpip/link/sniffer/sniffer.go
@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/buffer"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
+	"gvisor.dev/gvisor/pkg/tcpip/link/nested"
 	"gvisor.dev/gvisor/pkg/tcpip/stack"
 )
 
@@ -48,18 +49,21 @@ var LogPackets uint32 = 1
 var LogPacketsToPCAP uint32 = 1
 
 type endpoint struct {
-	dispatcher stack.NetworkDispatcher
-	lower      stack.LinkEndpoint
+	nested.Endpoint
 	writer     io.Writer
 	maxPCAPLen uint32
 }
 
+var _ stack.GSOEndpoint = (*endpoint)(nil)
+var _ stack.LinkEndpoint = (*endpoint)(nil)
+var _ stack.NetworkDispatcher = (*endpoint)(nil)
+
 // New creates a new sniffer link-layer endpoint. It wraps around another
 // endpoint and logs packets and they traverse the endpoint.
 func New(lower stack.LinkEndpoint) stack.LinkEndpoint {
-	return &endpoint{
-		lower: lower,
-	}
+	sniffer := &endpoint{}
+	sniffer.Endpoint.Init(lower, sniffer)
+	return sniffer
 }
 
 func zoneOffset() (int32, error) {
@@ -103,11 +107,12 @@ func NewWithWriter(lower stack.LinkEndpoint, writer io.Writer, snapLen uint32) (
 	if err := writePCAPHeader(writer, snapLen); err != nil {
 		return nil, err
 	}
-	return &endpoint{
-		lower:      lower,
+	sniffer := &endpoint{
 		writer:     writer,
 		maxPCAPLen: snapLen,
-	}, nil
+	}
+	sniffer.Endpoint.Init(lower, sniffer)
+	return sniffer, nil
 }
 
 // DeliverNetworkPacket implements the stack.NetworkDispatcher interface. It is
@@ -115,50 +120,7 @@ func NewWithWriter(lower stack.LinkEndpoint, writer io.Writer, snapLen uint32) (
 // logs the packet before forwarding to the actual dispatcher.
 func (e *endpoint) DeliverNetworkPacket(remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
 	e.dumpPacket("recv", nil, protocol, pkt)
-	e.dispatcher.DeliverNetworkPacket(remote, local, protocol, pkt)
-}
-
-// Attach implements the stack.LinkEndpoint interface. It saves the dispatcher
-// and registers with the lower endpoint as its dispatcher so that "e" is called
-// for inbound packets.
-func (e *endpoint) Attach(dispatcher stack.NetworkDispatcher) {
-	e.dispatcher = dispatcher
-	e.lower.Attach(e)
-}
-
-// IsAttached implements stack.LinkEndpoint.IsAttached.
-func (e *endpoint) IsAttached() bool {
-	return e.dispatcher != nil
-}
-
-// MTU implements stack.LinkEndpoint.MTU. It just forwards the request to the
-// lower endpoint.
-func (e *endpoint) MTU() uint32 {
-	return e.lower.MTU()
-}
-
-// Capabilities implements stack.LinkEndpoint.Capabilities. It just forwards the
-// request to the lower endpoint.
-func (e *endpoint) Capabilities() stack.LinkEndpointCapabilities {
-	return e.lower.Capabilities()
-}
-
-// MaxHeaderLength implements the stack.LinkEndpoint interface. It just forwards
-// the request to the lower endpoint.
-func (e *endpoint) MaxHeaderLength() uint16 {
-	return e.lower.MaxHeaderLength()
-}
-
-func (e *endpoint) LinkAddress() tcpip.LinkAddress {
-	return e.lower.LinkAddress()
-}
-
-// GSOMaxSize returns the maximum GSO packet size.
-func (e *endpoint) GSOMaxSize() uint32 {
-	if gso, ok := e.lower.(stack.GSOEndpoint); ok {
-		return gso.GSOMaxSize()
-	}
-	return 0
+	e.Endpoint.DeliverNetworkPacket(remote, local, protocol, pkt)
 }
 
 func (e *endpoint) dumpPacket(prefix string, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) {
@@ -203,7 +165,7 @@ func (e *endpoint) dumpPacket(prefix string, gso *stack.GSO, protocol tcpip.Netw
 // forwards the request to the lower endpoint.
 func (e *endpoint) WritePacket(r *stack.Route, gso *stack.GSO, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer) *tcpip.Error {
 	e.dumpPacket("send", gso, protocol, pkt)
-	return e.lower.WritePacket(r, gso, protocol, pkt)
+	return e.Endpoint.WritePacket(r, gso, protocol, pkt)
 }
 
 // WritePackets implements the stack.LinkEndpoint interface. It is called by
@@ -213,7 +175,7 @@ func (e *endpoint) WritePackets(r *stack.Route, gso *stack.GSO, pkts stack.Packe
 	for pkt := pkts.Front(); pkt != nil; pkt = pkt.Next() {
 		e.dumpPacket("send", gso, protocol, pkt)
 	}
-	return e.lower.WritePackets(r, gso, pkts, protocol)
+	return e.Endpoint.WritePackets(r, gso, pkts, protocol)
 }
 
 // WriteRawPacket implements stack.LinkEndpoint.WriteRawPacket.
@@ -221,12 +183,9 @@ func (e *endpoint) WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error {
 	e.dumpPacket("send", nil, 0, &stack.PacketBuffer{
 		Data: vv,
 	})
-	return e.lower.WriteRawPacket(vv)
+	return e.Endpoint.WriteRawPacket(vv)
 }
 
-// Wait implements stack.LinkEndpoint.Wait.
-func (e *endpoint) Wait() { e.lower.Wait() }
-
 func logPacket(prefix string, protocol tcpip.NetworkProtocolNumber, pkt *stack.PacketBuffer, gso *stack.GSO) {
 	// Figure out the network layer info.
 	var transProto uint8