3 files changed, 9 insertions, 73 deletions
diff --git a/pkg/tcpip/header/ipv6.go b/pkg/tcpip/header/ipv6.go
index e606e3463..093850e25 100644
--- a/pkg/tcpip/header/ipv6.go
+++ b/pkg/tcpip/header/ipv6.go
@@ -76,13 +76,6 @@ const (
 	// IPv6Version is the version of the ipv6 protocol.
 	IPv6Version = 6
 
-	// IPv6AllNodesMulticastAddress is a link-local multicast group that
-	// all IPv6 nodes MUST join, as per RFC 4291, section 2.8. Packets
-	// destined to this address will reach all nodes on a link.
-	//
-	// The address is ff02::1.
-	IPv6AllNodesMulticastAddress tcpip.Address = "\xff\x02\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01"
-
 	// IPv6MinimumMTU is the minimum MTU required by IPv6, per RFC 2460,
 	// section 5.
 	IPv6MinimumMTU = 1280
diff --git a/pkg/tcpip/stack/nic.go b/pkg/tcpip/stack/nic.go
index 249a19946..43719085e 100644
--- a/pkg/tcpip/stack/nic.go
+++ b/pkg/tcpip/stack/nic.go
@@ -102,25 +102,6 @@ func newNIC(stack *Stack, id tcpip.NICID, name string, ep LinkEndpoint, loopback
 	}
 }
 
-// enable enables the NIC. enable will attach the link to its LinkEndpoint and
-// join the IPv6 All-Nodes Multicast address (ff02::1).
-func (n *NIC) enable() *tcpip.Error {
-	n.attachLinkEndpoint()
-
-	// Join the IPv6 All-Nodes Multicast group if the stack is configured to
-	// use IPv6. This is required to ensure that this node properly receives
-	// and responds to the various NDP messages that are destined to the
-	// all-nodes multicast address. An example is the Neighbor Advertisement
-	// when we perform Duplicate Address Detection, or Router Advertisement
-	// when we do Router Discovery. See RFC 4862, section 5.4.2 and RFC 4861
-	// section 4.2 for more information.
-	if _, ok := n.stack.networkProtocols[header.IPv6ProtocolNumber]; ok {
-		return n.joinGroup(header.IPv6ProtocolNumber, header.IPv6AllNodesMulticastAddress)
-	}
-
-	return nil
-}
-
 // attachLinkEndpoint attaches the NIC to the endpoint, which will enable it
 // to start delivering packets.
 func (n *NIC) attachLinkEndpoint() {
@@ -358,15 +339,6 @@ func (n *NIC) addAddressLocked(protocolAddress tcpip.ProtocolAddress, peb Primar
 		}
 	}
 
-	// If we are adding an IPv6 address, join the solicited-node multicast
-	// address for a unicast protocolAddress.
-	if protocolAddress.Protocol == header.IPv6ProtocolNumber && !header.IsV6MulticastAddress(protocolAddress.AddressWithPrefix.Address) {
-		snmc := header.SolicitedNodeAddr(protocolAddress.AddressWithPrefix.Address)
-		if err := n.joinGroupLocked(protocolAddress.Protocol, snmc); err != nil {
-			return nil, err
-		}
-	}
-
 	n.endpoints[id] = ref
 
 	l, ok := n.primary[protocolAddress.Protocol]
@@ -495,27 +467,13 @@ func (n *NIC) removeEndpoint(r *referencedNetworkEndpoint) {
 }
 
 func (n *NIC) removePermanentAddressLocked(addr tcpip.Address) *tcpip.Error {
-	r, ok := n.endpoints[NetworkEndpointID{addr}]
-	if !ok || r.getKind() != permanent {
+	r := n.endpoints[NetworkEndpointID{addr}]
+	if r == nil || r.getKind() != permanent {
 		return tcpip.ErrBadLocalAddress
 	}
 
 	r.setKind(permanentExpired)
-	if !r.decRefLocked() {
-		// The endpoint still has references to it.
-		return nil
-	}
-
-	// At this point the endpoint is deleted.
-
-	// If we are removing an IPv6 address, leave the solicited-node
-	// multicast address for a unicast addr.
-	if r.protocol == header.IPv6ProtocolNumber && !header.IsV6MulticastAddress(addr) {
-		snmc := header.SolicitedNodeAddr(addr)
-		if err := n.leaveGroupLocked(snmc); err != nil {
-			return err
-		}
-	}
+	r.decRefLocked()
 
 	return nil
 }
@@ -533,13 +491,6 @@ func (n *NIC) joinGroup(protocol tcpip.NetworkProtocolNumber, addr tcpip.Address
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	return n.joinGroupLocked(protocol, addr)
-}
-
-// joinGroupLocked adds a new endpoint for the given multicast address, if none
-// exists yet. Otherwise it just increments its count. n MUST be locked before
-// joinGroupLocked is called.
-func (n *NIC) joinGroupLocked(protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) *tcpip.Error {
 	id := NetworkEndpointID{addr}
 	joins := n.mcastJoins[id]
 	if joins == 0 {
@@ -567,13 +518,6 @@ func (n *NIC) leaveGroup(addr tcpip.Address) *tcpip.Error {
 	n.mu.Lock()
 	defer n.mu.Unlock()
 
-	return n.leaveGroupLocked(addr)
-}
-
-// leaveGroupLocked decrements the count for the given multicast address, and
-// when it reaches zero removes the endpoint for this address. n MUST be locked
-// before leaveGroupLocked is called.
-func (n *NIC) leaveGroupLocked(addr tcpip.Address) *tcpip.Error {
 	id := NetworkEndpointID{addr}
 	joins := n.mcastJoins[id]
 	switch joins {
@@ -858,14 +802,11 @@ func (r *referencedNetworkEndpoint) decRef() {
 }
 
 // decRefLocked is the same as decRef but assumes that the NIC.mu mutex is
-// locked. Returns true if the endpoint was removed.
-func (r *referencedNetworkEndpoint) decRefLocked() bool {
+// locked.
+func (r *referencedNetworkEndpoint) decRefLocked() {
 	if atomic.AddInt32(&r.refs, -1) == 0 {
 		r.nic.removeEndpointLocked(r)
-		return true
 	}
-
-	return false
 }
 
 // incRef increments the ref count. It must only be called when the caller is
diff --git a/pkg/tcpip/stack/stack.go b/pkg/tcpip/stack/stack.go
index 1fe21b68e..a961e8ebe 100644
--- a/pkg/tcpip/stack/stack.go
+++ b/pkg/tcpip/stack/stack.go
@@ -633,7 +633,7 @@ func (s *Stack) createNIC(id tcpip.NICID, name string, ep LinkEndpoint, enabled,
 
 	s.nics[id] = n
 	if enabled {
-		return n.enable()
+		n.attachLinkEndpoint()
 	}
 
 	return nil
@@ -680,7 +680,9 @@ func (s *Stack) EnableNIC(id tcpip.NICID) *tcpip.Error {
 		return tcpip.ErrUnknownNICID
 	}
 
-	return nic.enable()
+	nic.attachLinkEndpoint()
+
+	return nil
 }
 
 // CheckNIC checks if a NIC is usable.