Expose address deprecation on Stack

Add a method for setting an address to be deprecated/preferred to
AddressableEndpoint, so that addresses added from outside the stack
can be deprecated/renewed respectively, e.g. by a DHCPv6 client.

PiperOrigin-RevId: 426435598

pkg/tcpip/network/ipv4/ipv4.go

@@ -1053,6 +1053,13 @@ func (e *endpoint) RemovePermanentAddress(addr tcpip.Address) tcpip.Error {
 	return e.addressableEndpointState.RemovePermanentAddress(addr)
 }
 
+// SetDeprecated implements stack.AddressableEndpoint.
+func (e *endpoint) SetDeprecated(addr tcpip.Address, deprecated bool) tcpip.Error {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.addressableEndpointState.SetDeprecated(addr, deprecated)
+}
+
 // MainAddress implements stack.AddressableEndpoint.
 func (e *endpoint) MainAddress() tcpip.AddressWithPrefix {
 	e.mu.RLock()

pkg/tcpip/network/ipv6/ipv6.go

@@ -1681,6 +1681,13 @@ func (e *endpoint) getAddressRLocked(localAddr tcpip.Address) stack.AddressEndpo
 	return e.mu.addressableEndpointState.GetAddress(localAddr)
 }
 
+// SetDeprecated implements stack.AddressableEndpoint.
+func (e *endpoint) SetDeprecated(addr tcpip.Address, deprecated bool) tcpip.Error {
+	e.mu.RLock()
+	defer e.mu.RUnlock()
+	return e.mu.addressableEndpointState.SetDeprecated(addr, deprecated)
+}
+
 // MainAddress implements stack.AddressableEndpoint.
 func (e *endpoint) MainAddress() tcpip.AddressWithPrefix {
 	e.mu.RLock()

pkg/tcpip/stack/addressable_endpoint_state.go

@@ -374,6 +374,19 @@ func (a *AddressableEndpointState) decAddressRefLocked(addrState *addressState)
 	a.releaseAddressStateLocked(addrState)
 }
 
+// SetDeprecated implements stack.AddressableEndpoint.
+func (a *AddressableEndpointState) SetDeprecated(addr tcpip.Address, deprecated bool) tcpip.Error {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+
+	addrState, ok := a.mu.endpoints[addr]
+	if !ok {
+		return &tcpip.ErrBadLocalAddress{}
+	}
+	addrState.SetDeprecated(deprecated)
+	return nil
+}
+
 // MainAddress implements AddressableEndpoint.
 func (a *AddressableEndpointState) MainAddress() tcpip.AddressWithPrefix {
 	a.mu.RLock()

pkg/tcpip/stack/nic.go

@@ -591,6 +591,24 @@ func (n *nic) removeAddress(addr tcpip.Address) tcpip.Error {
 	return &tcpip.ErrBadLocalAddress{}
 }
 
+func (n *nic) setAddressDeprecated(addr tcpip.Address, deprecated bool) tcpip.Error {
+	for _, ep := range n.networkEndpoints {
+		ep, ok := ep.(AddressableEndpoint)
+		if !ok {
+			continue
+		}
+
+		switch err := ep.SetDeprecated(addr, deprecated); err.(type) {
+		case *tcpip.ErrBadLocalAddress:
+			continue
+		default:
+			return err
+		}
+	}
+
+	return &tcpip.ErrBadLocalAddress{}
+}
+
 func (n *nic) getLinkAddress(addr, localAddr tcpip.Address, protocol tcpip.NetworkProtocolNumber, onResolve func(LinkResolutionResult)) tcpip.Error {
 	linkRes, ok := n.linkAddrResolvers[protocol]
 	if !ok {

pkg/tcpip/stack/registration.go

@@ -491,6 +491,12 @@ type AddressableEndpoint interface {
 	// permanent address.
 	RemovePermanentAddress(addr tcpip.Address) tcpip.Error
 
+	// SetDeprecated sets whether the address should be deprecated or not.
+	//
+	// Returns *tcpip.ErrBadLocalAddress if the endpoint does not have the passed
+	// address.
+	SetDeprecated(addr tcpip.Address, deprecated bool) tcpip.Error
+
 	// MainAddress returns the endpoint's primary permanent address.
 	MainAddress() tcpip.AddressWithPrefix
 

pkg/tcpip/stack/stack.go

@@ -943,6 +943,18 @@ func (s *Stack) RemoveAddress(id tcpip.NICID, addr tcpip.Address) tcpip.Error {
 	return &tcpip.ErrUnknownNICID{}
 }
 
+// SetAddressDeprecated sets an address to be deprecated or preferred.
+func (s *Stack) SetAddressDeprecated(id tcpip.NICID, addr tcpip.Address, deprecated bool) tcpip.Error {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	if nic, ok := s.nics[id]; ok {
+		return nic.setAddressDeprecated(addr, deprecated)
+	}
+
+	return &tcpip.ErrUnknownNICID{}
+}
+
 // AllAddresses returns a map of NICIDs to their protocol addresses (primary
 // and non-primary).
 func (s *Stack) AllAddresses() map[tcpip.NICID][]tcpip.ProtocolAddress {

pkg/tcpip/stack/stack_test.go

@@ -2980,7 +2980,7 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) {
 		properties stack.AddressProperties
 	}
 
-	// Rule 3 is not tested here, and is instead tested by NDP's AutoGenAddr test.
+	// Rule 3 is also tested by NDP's AutoGenAddr test.
 	tests := []struct {
 		name                                   string
 		slaacPrefixForTempAddrBeforeNICAddrAdd tcpip.AddressWithPrefix
@@ -3101,6 +3101,35 @@ func TestIPv6SourceAddressSelectionScopeAndSameAddress(t *testing.T) {
 			expectedLocalAddr: linkLocalAddr1,
 		},
 
+		// Test Rule 3 of RFC 6724 section 5 (avoid deprecated addresses).
+		{
+			name: "Deprecated least preferred (last address)",
+			nicAddrs: []addressWithProperties{
+				{addr: globalAddr1},
+				{
+					addr: globalAddr2,
+					properties: stack.AddressProperties{
+						Deprecated: true,
+					},
+				},
+			},
+			remoteAddr:        globalAddr3,
+			expectedLocalAddr: globalAddr1,
+		},
+		{
+			name: "Deprecated least preferred (first address)",
+			nicAddrs: []addressWithProperties{
+				{
+					addr: globalAddr2,
+					properties: stack.AddressProperties{
+						Deprecated: true,
+					},
+				},
+				{addr: globalAddr1},
+			},
+			remoteAddr:        globalAddr3,
+			expectedLocalAddr: globalAddr1,
+		},
 		// Test Rule 6 of 6724 section 5 (prefer matching label).
 		{
 			name: "Unique Local most preferred (last address)",