Merge release-20200211.0-62-ga155a23 (automated)

2 files changed, 12 insertions, 18 deletions

diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index b2be18e47..862954ab2 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -44,8 +44,7 @@ type NIC struct {
 	linkEP  LinkEndpoint
 	context NICContext
 
-	stats  NICStats
-	attach sync.Once
+	stats NICStats
 
 	mu struct {
 		sync.RWMutex
@@ -141,6 +140,8 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, ctx NICC
 		nic.mu.packetEPs[netProto.Number()] = []PacketEndpoint{}
 	}
 
+	nic.linkEP.Attach(nic)
+
 	return nic
 }
 
@@ -200,14 +201,16 @@ func (n *NIC) disable() *tcpip.Error {
 		}
 	}
 
-	// TODO(b/147015577): Should n detach from its LinkEndpoint?
-
 	n.mu.enabled = false
 	return nil
 }
 
-// enable enables n. enable will attach the nic to its LinkEndpoint and
-// join the IPv6 All-Nodes Multicast address (ff02::1).
+// enable enables n.
+//
+// If the stack has IPv6 enabled, enable will join the IPv6 All-Nodes Multicast
+// address (ff02::1), start DAD for permanent addresses, and start soliciting
+// routers if the stack is not operating as a router. If the stack is also
+// configured to auto-generate a link-local address, one will be generated.
 func (n *NIC) enable() *tcpip.Error {
 	n.mu.RLock()
 	enabled := n.mu.enabled
@@ -225,8 +228,6 @@ func (n *NIC) enable() *tcpip.Error {
 
 	n.mu.enabled = true
 
-	n.attachLinkEndpoint()
-
 	// Create an endpoint to receive broadcast packets on this interface.
 	if _, ok := n.stack.networkProtocols[header.IPv4ProtocolNumber]; ok {
 		if _, err := n.addAddressLocked(ipv4BroadcastAddr, NeverPrimaryEndpoint, permanent, static, false /* deprecated */); err != nil {
@@ -321,14 +322,6 @@ func (n *NIC) becomeIPv6Host() {
 	n.mu.ndp.startSolicitingRouters()
 }
 
-// attachLinkEndpoint attaches the NIC to the endpoint, which will enable it
-// to start delivering packets.
-func (n *NIC) attachLinkEndpoint() {
-	n.attach.Do(func() {
-		n.linkEP.Attach(n)
-	})
-}
-
 // setPromiscuousMode enables or disables promiscuous mode.
 func (n *NIC) setPromiscuousMode(enable bool) {
 	n.mu.Lock()
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index fabc976a7..f0ed76fbe 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -881,6 +881,8 @@ type NICOptions struct {
 // CreateNICWithOptions creates a NIC with the provided id, LinkEndpoint, and
 // NICOptions. See the documentation on type NICOptions for details on how
 // NICs can be configured.
+//
+// LinkEndpoint.Attach will be called to bind ep with a NetworkDispatcher.
 func (s *Stack) CreateNICWithOptions(id tcpip.NICID, ep LinkEndpoint, opts NICOptions) *tcpip.Error {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -900,7 +902,6 @@ func (s *Stack) CreateNICWithOptions(id tcpip.NICID, ep LinkEndpoint, opts NICOp
 	}
 
 	n := newNIC(s, id, opts.Name, ep, opts.Context)
-
 	s.nics[id] = n
 	if !opts.Disabled {
 		return n.enable()
@@ -910,7 +911,7 @@ func (s *Stack) CreateNICWithOptions(id tcpip.NICID, ep LinkEndpoint, opts NICOp
 }
 
 // CreateNIC creates a NIC with the provided id and LinkEndpoint and calls
-// `LinkEndpoint.Attach` to start delivering packets to it.
+// LinkEndpoint.Attach to bind ep with a NetworkDispatcher.
 func (s *Stack) CreateNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error {
 	return s.CreateNICWithOptions(id, ep, NICOptions{})
 }