Do not perform MLD for certain multicast scopes

...as per RFC 2710 section 5 page 10.

Test: ipv6_test.TestMLDSkipProtocol
PiperOrigin-RevId: 367031126

2 files changed, 22 insertions, 62 deletions

diff --git a/pkg/tcpip/network/internal/ip/generic_multicast_protocol.go b/pkg/tcpip/network/internal/ip/generic_multicast_protocol.go
index b9f129728..ac35d81e7 100644
--- a/pkg/tcpip/network/internal/ip/generic_multicast_protocol.go
+++ b/pkg/tcpip/network/internal/ip/generic_multicast_protocol.go
@@ -156,14 +156,6 @@ type GenericMulticastProtocolOptions struct {
 	//
 	// Unsolicited reports are transmitted when a group is newly joined.
 	MaxUnsolicitedReportDelay time.Duration
-
-	// AllNodesAddress is a multicast address that all nodes on a network should
-	// be a member of.
-	//
-	// This address will not have the generic multicast protocol performed on it;
-	// it will be left in the non member/listener state, and packets will never
-	// be sent for it.
-	AllNodesAddress tcpip.Address
 }
 
 // MulticastGroupProtocol is a multicast group protocol whose core state machine
@@ -188,6 +180,10 @@ type MulticastGroupProtocol interface {
 
 	// SendLeave sends a multicast leave for the specified group address.
 	SendLeave(groupAddress tcpip.Address) tcpip.Error
+
+	// ShouldPerformProtocol returns true iff the protocol should be performed for
+	// the specified group.
+	ShouldPerformProtocol(tcpip.Address) bool
 }
 
 // GenericMulticastProtocolState is the per interface generic multicast protocol
@@ -455,20 +451,7 @@ func (g *GenericMulticastProtocolState) initializeNewMemberLocked(groupAddress t
 
 	info.lastToSendReport = false
 
-	if groupAddress == g.opts.AllNodesAddress {
-		// As per RFC 2236 section 6 page 10 (for IGMPv2),
-		//
-		//   The all-systems group (address 224.0.0.1) is handled as a special
-		//   case. The host starts in Idle Member state for that group on every
-		//   interface, never transitions to another state, and never sends a
-		//   report for that group.
-		//
-		// As per RFC 2710 section 5 page 10 (for MLDv1),
-		//
-		//   The link-scope all-nodes address (FF02::1) is handled as a special
-		//   case. The node starts in Idle Listener state for that address on
-		//   every interface, never transitions to another state, and never sends
-		//   a Report or Done for that address.
+	if !g.opts.Protocol.ShouldPerformProtocol(groupAddress) {
 		info.state = idleMember
 		return
 	}
@@ -537,20 +520,7 @@ func (g *GenericMulticastProtocolState) maybeSendLeave(groupAddress tcpip.Addres
 		return
 	}
 
-	if groupAddress == g.opts.AllNodesAddress {
-		// As per RFC 2236 section 6 page 10 (for IGMPv2),
-		//
-		//   The all-systems group (address 224.0.0.1) is handled as a special
-		//   case. The host starts in Idle Member state for that group on every
-		//   interface, never transitions to another state, and never sends a
-		//   report for that group.
-		//
-		// As per RFC 2710 section 5 page 10 (for MLDv1),
-		//
-		//   The link-scope all-nodes address (FF02::1) is handled as a special
-		//   case. The node starts in Idle Listener state for that address on
-		//   every interface, never transitions to another state, and never sends
-		//   a Report or Done for that address.
+	if !g.opts.Protocol.ShouldPerformProtocol(groupAddress) {
 		return
 	}
 
@@ -627,20 +597,7 @@ func (g *GenericMulticastProtocolState) setDelayTimerForAddressRLocked(groupAddr
 		return
 	}
 
-	if groupAddress == g.opts.AllNodesAddress {
-		// As per RFC 2236 section 6 page 10 (for IGMPv2),
-		//
-		//   The all-systems group (address 224.0.0.1) is handled as a special
-		//   case. The host starts in Idle Member state for that group on every
-		//   interface, never transitions to another state, and never sends a
-		//   report for that group.
-		//
-		// As per RFC 2710 section 5 page 10 (for MLDv1),
-		//
-		//   The link-scope all-nodes address (FF02::1) is handled as a special
-		//   case. The node starts in Idle Listener state for that address on
-		//   every interface, never transitions to another state, and never sends
-		//   a Report or Done for that address.
+	if !g.opts.Protocol.ShouldPerformProtocol(groupAddress) {
 		return
 	}
 
diff --git a/pkg/tcpip/network/internal/ip/generic_multicast_protocol_test.go b/pkg/tcpip/network/internal/ip/generic_multicast_protocol_test.go
index 381460c82..0b51563cd 100644
--- a/pkg/tcpip/network/internal/ip/generic_multicast_protocol_test.go
+++ b/pkg/tcpip/network/internal/ip/generic_multicast_protocol_test.go
@@ -43,6 +43,8 @@ type mockMulticastGroupProtocolProtectedFields struct {
 type mockMulticastGroupProtocol struct {
 	t *testing.T
 
+	skipProtocolAddress tcpip.Address
+
 	mu mockMulticastGroupProtocolProtectedFields
 }
 
@@ -165,6 +167,11 @@ func (m *mockMulticastGroupProtocol) SendLeave(groupAddress tcpip.Address) tcpip
 	return nil
 }
 
+// ShouldPerformProtocol implements ip.MulticastGroupProtocol.
+func (m *mockMulticastGroupProtocol) ShouldPerformProtocol(groupAddress tcpip.Address) bool {
+	return groupAddress != m.skipProtocolAddress
+}
+
 func (m *mockMulticastGroupProtocol) check(sendReportGroupAddresses []tcpip.Address, sendLeaveGroupAddresses []tcpip.Address) string {
 	m.mu.Lock()
 	defer m.mu.Unlock()
@@ -193,10 +200,11 @@ func (m *mockMulticastGroupProtocol) check(sendReportGroupAddresses []tcpip.Addr
 		cmp.FilterPath(
 			func(p cmp.Path) bool {
 				switch p.Last().String() {
-				case ".RWMutex", ".t", ".makeQueuePackets", ".disabled", ".genericMulticastGroup":
+				case ".RWMutex", ".t", ".makeQueuePackets", ".disabled", ".genericMulticastGroup", ".skipProtocolAddress":
 					return true
+				default:
+					return false
 				}
-				return false
 			},
 			cmp.Ignore(),
 		),
@@ -225,14 +233,13 @@ func TestJoinGroup(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			mgp := mockMulticastGroupProtocol{t: t}
+			mgp := mockMulticastGroupProtocol{t: t, skipProtocolAddress: addr2}
 			clock := faketime.NewManualClock()
 
 			mgp.init(ip.GenericMulticastProtocolOptions{
 				Rand:                      rand.New(rand.NewSource(0)),
 				Clock:                     clock,
 				MaxUnsolicitedReportDelay: maxUnsolicitedReportDelay,
-				AllNodesAddress:           addr2,
 			})
 
 			// Joining a group should send a report immediately and another after
@@ -279,14 +286,13 @@ func TestLeaveGroup(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			mgp := mockMulticastGroupProtocol{t: t}
+			mgp := mockMulticastGroupProtocol{t: t, skipProtocolAddress: addr2}
 			clock := faketime.NewManualClock()
 
 			mgp.init(ip.GenericMulticastProtocolOptions{
 				Rand:                      rand.New(rand.NewSource(1)),
 				Clock:                     clock,
 				MaxUnsolicitedReportDelay: maxUnsolicitedReportDelay,
-				AllNodesAddress:           addr2,
 			})
 
 			mgp.joinGroup(test.addr)
@@ -356,14 +362,13 @@ func TestHandleReport(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			mgp := mockMulticastGroupProtocol{t: t}
+			mgp := mockMulticastGroupProtocol{t: t, skipProtocolAddress: addr3}
 			clock := faketime.NewManualClock()
 
 			mgp.init(ip.GenericMulticastProtocolOptions{
 				Rand:                      rand.New(rand.NewSource(2)),
 				Clock:                     clock,
 				MaxUnsolicitedReportDelay: maxUnsolicitedReportDelay,
-				AllNodesAddress:           addr3,
 			})
 
 			mgp.joinGroup(addr1)
@@ -446,14 +451,13 @@ func TestHandleQuery(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			mgp := mockMulticastGroupProtocol{t: t}
+			mgp := mockMulticastGroupProtocol{t: t, skipProtocolAddress: addr3}
 			clock := faketime.NewManualClock()
 
 			mgp.init(ip.GenericMulticastProtocolOptions{
 				Rand:                      rand.New(rand.NewSource(3)),
 				Clock:                     clock,
 				MaxUnsolicitedReportDelay: maxUnsolicitedReportDelay,
-				AllNodesAddress:           addr3,
 			})
 
 			mgp.joinGroup(addr1)
@@ -574,14 +578,13 @@ func TestJoinCount(t *testing.T) {
 }
 
 func TestMakeAllNonMemberAndInitialize(t *testing.T) {
-	mgp := mockMulticastGroupProtocol{t: t}
+	mgp := mockMulticastGroupProtocol{t: t, skipProtocolAddress: addr3}
 	clock := faketime.NewManualClock()
 
 	mgp.init(ip.GenericMulticastProtocolOptions{
 		Rand:                      rand.New(rand.NewSource(3)),
 		Clock:                     clock,
 		MaxUnsolicitedReportDelay: maxUnsolicitedReportDelay,
-		AllNodesAddress:           addr3,
 	})
 
 	mgp.joinGroup(addr1)