Allow setting IGMP version

Updates #8346 PiperOrigin-RevId: 507927598
2026-05-22 17:12:49 -07:00 · 2023-02-07 17:17:54 -08:00
parent 155b64e4d8
commit 6080f5725e
3 changed files with 217 additions and 51 deletions
@@ -19,7 +19,6 @@ import (
 	"math"
 	"time"

-	"gvisor.dev/gvisor/pkg/atomicbitops"
 	"gvisor.dev/gvisor/pkg/bufferv2"
 	"gvisor.dev/gvisor/pkg/tcpip"
 	"gvisor.dev/gvisor/pkg/tcpip/header"
@@ -28,11 +27,6 @@ import (
 )

 const (
-	// igmpV1PresentDefault is the initial state for igmpV1Present in the
-	// igmpState. As per RFC 2236 Page 9 says "No IGMPv1 Router Present ... is
-	// the initial state."
-	igmpV1PresentDefault = 0
-
 	// v1RouterPresentTimeout from RFC 2236 Section 8.11, Page 18
 	// See note on igmpState.igmpV1Present for more detail.
 	v1RouterPresentTimeout = 400 * time.Second
@@ -51,6 +45,47 @@ const (
 	UnsolicitedReportIntervalMax = 10 * time.Second
 )

+type protocolMode int
+
+const (
+	protocolModeV2OrV3 protocolMode = iota
+	protocolModeV1
+	// protocolModeV1Compatibility is for maintaining compatibility with IGMPv1
+	// Routers.
+	//
+	// Per RFC 2236 Section 4 Page 6: "The IGMPv1 router expects Version 1
+	// Membership Reports in response to its Queries, and will not pay
+	// attention to Version 2 Membership Reports.  Therefore, a state variable
+	// MUST be kept for each interface, describing whether the multicast
+	// Querier on that interface is running IGMPv1 or IGMPv2.  This variable
+	// MUST be based upon whether or not an IGMPv1 query was heard in the last
+	// [Version 1 Router Present Timeout] seconds".
+	protocolModeV1Compatibility
+)
+
+// IGMPVersion is the forced version of IGMP.
+type IGMPVersion int
+
+const (
+	_ IGMPVersion = iota
+	// IGMPVersion1 indicates IGMPv1.
+	IGMPVersion1
+	// IGMPVersion2 indicates IGMPv2. Note that IGMP may still fallback to V1
+	// compatibility mode as required by IGMPv2.
+	IGMPVersion2
+	// IGMPVersion3 indicates IGMPv3. Note that IGMP may still fallback to V2
+	// compatibility mode as required by IGMPv3.
+	IGMPVersion3
+)
+
+// IGMPEndpoint is a network endpoint that supports IGMP.
+type IGMPEndpoint interface {
+	// Sets the IGMP version.
+	//
+	// Returns the previous IGMP version.
+	SetIGMPVersion(IGMPVersion) IGMPVersion
+}
+
 // IGMPOptions holds options for IGMP.
 type IGMPOptions struct {
 	// Enabled indicates whether IGMP will be performed.
@@ -75,17 +110,8 @@ type igmpState struct {

 	genericMulticastProtocol ip.GenericMulticastProtocolState

-	// igmpV1Present is for maintaining compatibility with IGMPv1 Routers, from
-	// RFC 2236 Section 4 Page 6: "The IGMPv1 router expects Version 1
-	// Membership Reports in response to its Queries, and will not pay
-	// attention to Version 2 Membership Reports.  Therefore, a state variable
-	// MUST be kept for each interface, describing whether the multicast
-	// Querier on that interface is running IGMPv1 or IGMPv2.  This variable
-	// MUST be based upon whether or not an IGMPv1 query was heard in the last
-	// [Version 1 Router Present Timeout] seconds".
-	//
-	// Holds a value of 1 when true, 0 when false.
-	igmpV1Present atomicbitops.Uint32
+	// mode is used to configure the version of IGMP to perform.
+	mode protocolMode

 	// igmpV1Job is scheduled when this interface receives an IGMPv1 style
 	// message, upon expiration the igmpV1Present flag is cleared.
@@ -105,8 +131,12 @@ func (igmp *igmpState) Enabled() bool {
 // +checklocksread:igmp.ep.mu
 func (igmp *igmpState) SendReport(groupAddress tcpip.Address) (bool, tcpip.Error) {
 	igmpType := header.IGMPv2MembershipReport
-	if igmp.v1Present() {
+	switch igmp.mode {
+	case protocolModeV2OrV3:
+	case protocolModeV1, protocolModeV1Compatibility:
 		igmpType = header.IGMPv1MembershipReport
+	default:
+		panic(fmt.Sprintf("unrecognized mode = %d", igmp.mode))
 	}
 	return igmp.writePacket(groupAddress, groupAddress, igmpType)
 }
@@ -119,11 +149,15 @@ func (igmp *igmpState) SendLeave(groupAddress tcpip.Address) tcpip.Error {
 	// Querier is running IGMPv1, this action SHOULD be skipped. If the flag
 	// saying we were the last host to report is cleared, this action MAY be
 	// skipped."
-	if igmp.v1Present() {
+	switch igmp.mode {
+	case protocolModeV2OrV3:
+		_, err := igmp.writePacket(header.IPv4AllRoutersGroup, groupAddress, header.IGMPLeaveGroup)
+		return err
+	case protocolModeV1, protocolModeV1Compatibility:
 		return nil
+	default:
+		panic(fmt.Sprintf("unrecognized mode = %d", igmp.mode))
 	}
-	_, err := igmp.writePacket(header.IPv4AllRoutersGroup, groupAddress, header.IGMPLeaveGroup)
-	return err
 }

 // ShouldPerformProtocol implements ip.MulticastGroupProtocol.
@@ -251,9 +285,11 @@ func (igmp *igmpState) init(ep *endpoint) {
 		Protocol:                  igmp,
 		MaxUnsolicitedReportDelay: UnsolicitedReportIntervalMax,
 	})
-	igmp.igmpV1Present = atomicbitops.FromUint32(igmpV1PresentDefault)
+	// As per RFC 2236 Page 9 says "No IGMPv1 Router Present ... is
+	// the initial state.
+	igmp.mode = protocolModeV2OrV3
 	igmp.igmpV1Job = tcpip.NewJob(ep.protocol.stack.Clock(), &ep.mu, func() {
-		igmp.setV1Present(false)
+		igmp.mode = protocolModeV2OrV3
 	})
 }

@@ -381,21 +417,15 @@ func (igmp *igmpState) handleIGMP(pkt stack.PacketBufferPtr, hasRouterAlertOptio
 	}
 }

-func (igmp *igmpState) v1Present() bool {
-	return igmp.igmpV1Present.Load() == 1
-}
-
-func (igmp *igmpState) setV1Present(v bool) {
-	if v {
-		igmp.igmpV1Present.Store(1)
-	} else {
-		igmp.igmpV1Present.Store(0)
-	}
-}
-
 func (igmp *igmpState) resetV1Present() {
 	igmp.igmpV1Job.Cancel()
-	igmp.setV1Present(false)
+	switch igmp.mode {
+	case protocolModeV2OrV3, protocolModeV1:
+	case protocolModeV1Compatibility:
+		igmp.mode = protocolModeV2OrV3
+	default:
+		panic(fmt.Sprintf("unrecognized mode = %d", igmp.mode))
+	}
 }

 // handleMembershipQuery handles a membership query.
@@ -406,9 +436,16 @@ func (igmp *igmpState) handleMembershipQuery(groupAddress tcpip.Address, maxResp
 	// then change the state to note that an IGMPv1 router is present and
 	// schedule the query received Job.
 	if maxRespTime == 0 && igmp.Enabled() {
-		igmp.igmpV1Job.Cancel()
-		igmp.igmpV1Job.Schedule(v1RouterPresentTimeout)
-		igmp.setV1Present(true)
+		switch igmp.mode {
+		case protocolModeV2OrV3, protocolModeV1Compatibility:
+			igmp.igmpV1Job.Cancel()
+			igmp.igmpV1Job.Schedule(v1RouterPresentTimeout)
+			igmp.mode = protocolModeV1Compatibility
+		case protocolModeV1:
+		default:
+			panic(fmt.Sprintf("unrecognized mode = %d", igmp.mode))
+		}
+
 		maxRespTime = v1MaxRespTime
 	}

@@ -556,7 +593,44 @@ func (igmp *igmpState) initializeAll() {

 // sendQueuedReports attempts to send any reports that are queued for sending.
 //
-// +checklocksread:igmp.ep.mu
+// +checklocks:igmp.ep.mu
 func (igmp *igmpState) sendQueuedReports() {
 	igmp.genericMulticastProtocol.SendQueuedReportsLocked()
 }
+
+// setVersion sets the IGMP version.
+//
+// +checklocks:igmp.ep.mu
+func (igmp *igmpState) setVersion(v IGMPVersion) IGMPVersion {
+	prev := igmp.mode
+	igmp.igmpV1Job.Cancel()
+
+	var prevGenericModeV1 bool
+	switch v {
+	case IGMPVersion3:
+		prevGenericModeV1 = igmp.genericMulticastProtocol.SetV1ModeLocked(false)
+		igmp.mode = protocolModeV2OrV3
+	case IGMPVersion2:
+		// IGMPv1 and IGMPv2 map to V1 of the generic multicast protocol.
+		prevGenericModeV1 = igmp.genericMulticastProtocol.SetV1ModeLocked(true)
+		igmp.mode = protocolModeV2OrV3
+	case IGMPVersion1:
+		// IGMPv1 and IGMPv2 map to V1 of the generic multicast protocol.
+		prevGenericModeV1 = igmp.genericMulticastProtocol.SetV1ModeLocked(true)
+		igmp.mode = protocolModeV1
+	default:
+		panic(fmt.Sprintf("unrecognized version = %d", v))
+	}
+
+	switch prev {
+	case protocolModeV2OrV3, protocolModeV1Compatibility:
+		if prevGenericModeV1 {
+			return IGMPVersion2
+		}
+		return IGMPVersion3
+	case protocolModeV1:
+		return IGMPVersion1
+	default:
+		panic(fmt.Sprintf("unrecognized mode = %d", igmp.mode))
+	}
+}
@@ -43,7 +43,9 @@ var (
 	remoteAddr          = testutil.MustParse4("10.0.0.2")
 	multicastAddr1      = testutil.MustParse4("224.0.0.3")
 	multicastAddr2      = testutil.MustParse4("224.0.0.4")
-	unusedMulticastAddr = testutil.MustParse4("224.0.0.5")
+	multicastAddr3      = testutil.MustParse4("224.0.0.5")
+	multicastAddr4      = testutil.MustParse4("224.0.0.6")
+	unusedMulticastAddr = testutil.MustParse4("224.0.0.7")
 )

 // validateIgmpPacket checks that a passed packet is an IPv4 IGMP packet sent
@@ -276,16 +278,17 @@ func TestSendQueuedIGMPReports(t *testing.T) {

 			checkVersion := func() {
 				if test.v2Compatibility {
-					createAndInjectIGMPPacket(
-						e,
-						header.IGMPMembershipQuery,
-						1, /* maxRespTime */
-						header.IGMPTTL,
-						remoteAddr,
-						header.IPv4AllSystems,
-						unusedMulticastAddr,
-						true, /* hasRouterAlertOption */
-					)
+					ep, err := s.GetNetworkEndpoint(nicID, header.IPv4ProtocolNumber)
+					if err != nil {
+						t.Fatalf("s.GetNetworkEndpoint(%d, %d): %s", nicID, header.IPv4ProtocolNumber, err)
+					}
+
+					igmpEP, ok := ep.(ipv4.IGMPEndpoint)
+					if !ok {
+						t.Fatalf("got (%T).(%T) = (_, false), want = (_ true)", ep, igmpEP)
+					}
+
+					igmpEP.SetIGMPVersion(ipv4.IGMPVersion2)
 				}
 			}
 			protocolAddr := tcpip.ProtocolAddress{
@@ -505,3 +508,78 @@ func TestIGMPPacketValidation(t *testing.T) {
 		})
 	}
 }
+
+func TestSetIGMPVersion(t *testing.T) {
+	const nicID = 1
+
+	c := newIGMPTestContext(t, true /* igmpEnabled */)
+	defer c.cleanup()
+	s := c.s
+	e := c.ep
+
+	ep, err := s.GetNetworkEndpoint(nicID, header.IPv4ProtocolNumber)
+	if err != nil {
+		t.Fatalf("s.GetNetworkEndpoint(%d, %d): %s", nicID, header.IPv4ProtocolNumber, err)
+	}
+	igmpEP, ok := ep.(ipv4.IGMPEndpoint)
+	if !ok {
+		t.Fatalf("got (%T).(%T) = (_, false), want = (_ true)", ep, igmpEP)
+	}
+
+	protocolAddr := tcpip.ProtocolAddress{
+		Protocol:          ipv4.ProtocolNumber,
+		AddressWithPrefix: tcpip.AddressWithPrefix{Address: stackAddr, PrefixLen: defaultPrefixLength},
+	}
+	if err := s.AddProtocolAddress(nicID, protocolAddr, stack.AddressProperties{}); err != nil {
+		t.Fatalf("AddProtocolAddress(%d, %+v, {}): %s", nicID, protocolAddr, err)
+	}
+
+	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr1); err != nil {
+		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr1, err)
+	}
+	if p := e.Read(); p.IsNil() {
+		t.Fatal("expected a report message to be sent")
+	} else {
+		validateIgmpv3ReportPacket(t, p, stackAddr, multicastAddr1)
+		p.DecRef()
+	}
+
+	if got := igmpEP.SetIGMPVersion(ipv4.IGMPVersion2); got != ipv4.IGMPVersion3 {
+		t.Errorf("got igmpEP.SetIGMPVersion(%d) = %d, want = %d", ipv4.IGMPVersion2, got, ipv4.IGMPVersion3)
+	}
+	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr2); err != nil {
+		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr2, err)
+	}
+	if p := e.Read(); p.IsNil() {
+		t.Fatal("expected a report message to be sent")
+	} else {
+		validateIgmpPacket(t, p, header.IGMPv2MembershipReport, 0, stackAddr, multicastAddr2, multicastAddr2)
+		p.DecRef()
+	}
+
+	if got := igmpEP.SetIGMPVersion(ipv4.IGMPVersion1); got != ipv4.IGMPVersion2 {
+		t.Errorf("got igmpEP.SetIGMPVersion(%d) = %d, want = %d", ipv4.IGMPVersion1, got, ipv4.IGMPVersion2)
+	}
+	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr3); err != nil {
+		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr3, err)
+	}
+	if p := e.Read(); p.IsNil() {
+		t.Fatal("expected a report message to be sent")
+	} else {
+		validateIgmpPacket(t, p, header.IGMPv1MembershipReport, 0, stackAddr, multicastAddr3, multicastAddr3)
+		p.DecRef()
+	}
+
+	if got := igmpEP.SetIGMPVersion(ipv4.IGMPVersion3); got != ipv4.IGMPVersion1 {
+		t.Errorf("got igmpEP.SetIGMPVersion(%d) = %d, want = %d", ipv4.IGMPVersion3, got, ipv4.IGMPVersion1)
+	}
+	if err := s.JoinGroup(ipv4.ProtocolNumber, nicID, multicastAddr4); err != nil {
+		t.Fatalf("JoinGroup(ipv4, nic, %s) = %s", multicastAddr4, err)
+	}
+	if p := e.Read(); p.IsNil() {
+		t.Fatal("expected a report message to be sent")
+	} else {
+		validateIgmpv3ReportPacket(t, p, stackAddr, multicastAddr4)
+		p.DecRef()
+	}
+}
@@ -77,6 +77,7 @@ var _ stack.MulticastForwardingNetworkEndpoint = (*endpoint)(nil)
 var _ stack.GroupAddressableEndpoint = (*endpoint)(nil)
 var _ stack.AddressableEndpoint = (*endpoint)(nil)
 var _ stack.NetworkEndpoint = (*endpoint)(nil)
+var _ IGMPEndpoint = (*endpoint)(nil)

 type endpoint struct {
 	nic        stack.NetworkInterface
@@ -109,6 +110,19 @@ type endpoint struct {
 	igmp igmpState
 }

+// SetIGMPVersion implements IGMPEndpoint.
+func (e *endpoint) SetIGMPVersion(v IGMPVersion) IGMPVersion {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	return e.setIGMPVersionLocked(v)
+}
+
+// +checklocks:e.mu
+// +checklocksalias:e.igmp.ep.mu=e.mu
+func (e *endpoint) setIGMPVersionLocked(v IGMPVersion) IGMPVersion {
+	return e.igmp.setVersion(v)
+}
+
 // HandleLinkResolutionFailure implements stack.LinkResolvableNetworkEndpoint.
 func (e *endpoint) HandleLinkResolutionFailure(pkt stack.PacketBufferPtr) {
 	// If we are operating as a router, return an ICMP error to the original