diff options
Diffstat (limited to 'pkg/tcpip/network/ip')
| -rw-r--r-- | pkg/tcpip/network/ip/generic_multicast_protocol.go | 130 |
1 files changed, 122 insertions, 8 deletions
diff --git a/pkg/tcpip/network/ip/generic_multicast_protocol.go b/pkg/tcpip/network/ip/generic_multicast_protocol.go index c8c17ab15..f85c5ff9d 100644 --- a/pkg/tcpip/network/ip/generic_multicast_protocol.go +++ b/pkg/tcpip/network/ip/generic_multicast_protocol.go @@ -30,6 +30,23 @@ type hostState int // The states below are generic across IGMPv2 (RFC 2236 section 6) and MLDv1 // (RFC 2710 section 5). Even though the states are generic across both IGMPv2 // and MLDv1, IGMPv2 terminology will be used. +// +// ______________receive query______________ +// | | +// | _____send or receive report_____ | +// | | | | +// V | V | +// +-------+ +-----------+ +------------+ +-------------------+ +--------+ | +// | Non-M | | Pending-M | | Delaying-M | | Queued Delaying-M | | Idle-M | - +// +-------+ +-----------+ +------------+ +-------------------+ +--------+ +// | ^ | ^ | ^ | ^ +// | | | | | | | | +// ---------- ------- ---------- ------------- +// initialize new send inital fail to send send or receive +// group membership report delayed report report +// +// Not shown in the diagram above, but any state may transition into the non +// member state when a group is left. const ( // nonMember is the "'Non-Member' state, when the host does not belong to the // group on the interface. This is the initial state for all memberships on @@ -41,6 +58,15 @@ const ( // but without advertising the membership to the network. nonMember hostState = iota + // pendingMember is a newly joined member that is waiting to successfully send + // the initial set of reports. + // + // This is not an RFC defined state; it is an implementation specific state to + // track that the initial report needs to be sent. + // + // MAY NOT transition to the idle member state from this state. + pendingMember + // delayingMember is the "'Delaying Member' state, when the host belongs to // the group on the interface and has a report delay timer running for that // membership." @@ -48,6 +74,16 @@ const ( // 'Delaying Listener' is the MLDv1 term used to describe this state. delayingMember + // queuedDelayingMember is a delayingMember that failed to send a report after + // its delayed report timer fired. Hosts in this state are waiting to attempt + // retransmission of the delayed report. + // + // This is not an RFC defined state; it is an implementation specific state to + // track that the delayed report needs to be sent. + // + // May transition to idle member if a report is received for a group. + queuedDelayingMember + // idleMember is the "Idle Member" state, when the host belongs to the group // on the interface and does not have a report delay timer running for that // membership. @@ -56,6 +92,17 @@ const ( idleMember ) +func (s hostState) isDelayingMember() bool { + switch s { + case nonMember, pendingMember, idleMember: + return false + case delayingMember, queuedDelayingMember: + return true + default: + panic(fmt.Sprintf("unrecognized host state = %d", s)) + } +} + // multicastGroupState holds the Generic Multicast Protocol state for a // multicast group. type multicastGroupState struct { @@ -124,7 +171,10 @@ type GenericMulticastProtocolOptions struct { // can be represented by GenericMulticastProtocolState. type MulticastGroupProtocol interface { // SendReport sends a multicast report for the specified group address. - SendReport(groupAddress tcpip.Address) *tcpip.Error + // + // Returns false if the caller should queue the report to be sent later. Note, + // returning false does not mean that the receiver hit an error. + SendReport(groupAddress tcpip.Address) (sent bool, err *tcpip.Error) // SendLeave sends a multicast leave for the specified group address. SendLeave(groupAddress tcpip.Address) *tcpip.Error @@ -166,6 +216,9 @@ type GenericMulticastProtocolState struct { // // The GenericMulticastProtocolState will only grab the lock when timers/jobs // fire. +// +// Note: the methods on opts.Protocol will always be called while protocolMU is +// held. func (g *GenericMulticastProtocolState) Init(protocolMU *sync.RWMutex, opts GenericMulticastProtocolOptions) { if g.memberships != nil { panic("attempted to initialize generic membership protocol state twice") @@ -212,6 +265,29 @@ func (g *GenericMulticastProtocolState) InitializeGroupsLocked() { } } +// SendQueuedReportsLocked attempts to send reports for groups that failed to +// send reports during their last attempt. +// +// Precondition: g.protocolMU must be locked. +func (g *GenericMulticastProtocolState) SendQueuedReportsLocked() { + for groupAddress, info := range g.memberships { + switch info.state { + case nonMember, delayingMember, idleMember: + case pendingMember: + // pendingMembers failed to send their initial unsolicited report so try + // to send the report and queue the extra unsolicited reports. + g.maybeSendInitialReportLocked(groupAddress, &info) + case queuedDelayingMember: + // queuedDelayingMembers failed to send their delayed reports so try to + // send the report and transition them to the idle state. + g.maybeSendDelayedReportLocked(groupAddress, &info) + default: + panic(fmt.Sprintf("unrecognized host state = %d", info.state)) + } + g.memberships[groupAddress] = info + } +} + // JoinGroupLocked handles joining a new group. // // If dontInitialize is true, the group will be not be initialized and will be @@ -239,8 +315,7 @@ func (g *GenericMulticastProtocolState) JoinGroupLocked(groupAddress tcpip.Addre panic(fmt.Sprintf("expected to find group state for group = %s", groupAddress)) } - info.lastToSendReport = g.opts.Protocol.SendReport(groupAddress) == nil - info.state = idleMember + g.maybeSendDelayedReportLocked(groupAddress, &info) g.memberships[groupAddress] = info }), } @@ -347,7 +422,7 @@ func (g *GenericMulticastProtocolState) HandleReportLocked(groupAddress tcpip.Ad // multicast address while it has a timer running for that same address // on that interface, it stops its timer and does not send a Report for // that address, thus suppressing duplicate reports on the link. - if info, ok := g.memberships[groupAddress]; ok && info.state == delayingMember { + if info, ok := g.memberships[groupAddress]; ok && info.state.isDelayingMember() { info.delayedReportJob.Cancel() info.lastToSendReport = false info.state = idleMember @@ -360,10 +435,10 @@ func (g *GenericMulticastProtocolState) HandleReportLocked(groupAddress tcpip.Ad // Precondition: g.protocolMU must be locked. func (g *GenericMulticastProtocolState) initializeNewMemberLocked(groupAddress tcpip.Address, info *multicastGroupState) { if info.state != nonMember { - panic(fmt.Sprintf("state for group %s is not non-member; state = %d", groupAddress, info.state)) + panic(fmt.Sprintf("host must be in non-member state to be initialized; group = %s, state = %d", groupAddress, info.state)) } - info.state = idleMember + info.lastToSendReport = false if groupAddress == g.opts.AllNodesAddress { // As per RFC 2236 section 6 page 10 (for IGMPv2), @@ -379,9 +454,25 @@ func (g *GenericMulticastProtocolState) initializeNewMemberLocked(groupAddress t // 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. + info.state = idleMember return } + info.state = pendingMember + g.maybeSendInitialReportLocked(groupAddress, info) +} + +// maybeSendInitialReportLocked attempts to start transmission of the initial +// set of reports after newly joining a group. +// +// Host must be in pending member state. +// +// Precondition: g.protocolMU must be locked. +func (g *GenericMulticastProtocolState) maybeSendInitialReportLocked(groupAddress tcpip.Address, info *multicastGroupState) { + if info.state != pendingMember { + panic(fmt.Sprintf("host must be in pending member state to send initial reports; group = %s, state = %d", groupAddress, info.state)) + } + // As per RFC 2236 section 3 page 5 (for IGMPv2), // // When a host joins a multicast group, it should immediately transmit an @@ -399,8 +490,30 @@ func (g *GenericMulticastProtocolState) initializeNewMemberLocked(groupAddress t // // TODO(gvisor.dev/issue/4901): Support a configurable number of initial // unsolicited reports. - info.lastToSendReport = g.opts.Protocol.SendReport(groupAddress) == nil - g.setDelayTimerForAddressRLocked(groupAddress, info, g.opts.MaxUnsolicitedReportDelay) + sent, err := g.opts.Protocol.SendReport(groupAddress) + if err == nil && sent { + info.lastToSendReport = true + g.setDelayTimerForAddressRLocked(groupAddress, info, g.opts.MaxUnsolicitedReportDelay) + } +} + +// maybeSendDelayedReportLocked attempts to send the delayed report. +// +// Host must be in pending, delaying or queued delaying member state. +// +// Precondition: g.protocolMU must be locked. +func (g *GenericMulticastProtocolState) maybeSendDelayedReportLocked(groupAddress tcpip.Address, info *multicastGroupState) { + if !info.state.isDelayingMember() { + panic(fmt.Sprintf("host must be in delaying or queued delaying member state to send delayed reports; group = %s, state = %d", groupAddress, info.state)) + } + + sent, err := g.opts.Protocol.SendReport(groupAddress) + if err == nil && sent { + info.lastToSendReport = true + info.state = idleMember + } else { + info.state = queuedDelayingMember + } } // maybeSendLeave attempts to send a leave message. @@ -531,6 +644,7 @@ func (g *GenericMulticastProtocolState) setDelayTimerForAddressRLocked(groupAddr // TODO: Reset the timer if time remaining is greater than maxResponseTime. return } + info.state = delayingMember info.delayedReportJob.Cancel() info.delayedReportJob.Schedule(g.calculateDelayTimerDuration(maxResponseTime)) |