diff options
Diffstat (limited to 'pkg/tcpip/stack/ndp.go')
| -rw-r--r-- | pkg/tcpip/stack/ndp.go | 737 |
1 files changed, 609 insertions, 128 deletions
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index c11d62f97..526c7d6ff 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -119,6 +119,36 @@ const ( // identifier (IID) is 64 bits and an IPv6 address is 128 bits, so // 128 - 64 = 64. validPrefixLenForAutoGen = 64 + + // defaultAutoGenTempGlobalAddresses is the default configuration for whether + // or not to generate temporary SLAAC addresses. + defaultAutoGenTempGlobalAddresses = true + + // defaultMaxTempAddrValidLifetime is the default maximum valid lifetime + // for temporary SLAAC addresses generated as part of RFC 4941. + // + // Default = 7 days (from RFC 4941 section 5). + defaultMaxTempAddrValidLifetime = 7 * 24 * time.Hour + + // defaultMaxTempAddrPreferredLifetime is the default preferred lifetime + // for temporary SLAAC addresses generated as part of RFC 4941. + // + // Default = 1 day (from RFC 4941 section 5). + defaultMaxTempAddrPreferredLifetime = 24 * time.Hour + + // defaultRegenAdvanceDuration is the default duration before the deprecation + // of a temporary address when a new address will be generated. + // + // Default = 5s (from RFC 4941 section 5). + defaultRegenAdvanceDuration = 5 * time.Second + + // minRegenAdvanceDuration is the minimum duration before the deprecation + // of a temporary address when a new address will be generated. + minRegenAdvanceDuration = time.Duration(0) + + // maxSLAACAddrLocalRegenAttempts is the maximum number of times to attempt + // SLAAC address regenerations in response to a NIC-local conflict. + maxSLAACAddrLocalRegenAttempts = 10 ) var ( @@ -131,6 +161,37 @@ var ( // // Min = 2hrs. MinPrefixInformationValidLifetimeForUpdate = 2 * time.Hour + + // MaxDesyncFactor is the upper bound for the preferred lifetime's desync + // factor for temporary SLAAC addresses. + // + // This is exported as a variable (instead of a constant) so tests + // can update it to a smaller value. + // + // Must be greater than 0. + // + // Max = 10m (from RFC 4941 section 5). + MaxDesyncFactor = 10 * time.Minute + + // MinMaxTempAddrPreferredLifetime is the minimum value allowed for the + // maximum preferred lifetime for temporary SLAAC addresses. + // + // This is exported as a variable (instead of a constant) so tests + // can update it to a smaller value. + // + // This value guarantees that a temporary address will be preferred for at + // least 1hr if the SLAAC prefix is valid for at least that time. + MinMaxTempAddrPreferredLifetime = defaultRegenAdvanceDuration + MaxDesyncFactor + time.Hour + + // MinMaxTempAddrValidLifetime is the minimum value allowed for the + // maximum valid lifetime for temporary SLAAC addresses. + // + // This is exported as a variable (instead of a constant) so tests + // can update it to a smaller value. + // + // This value guarantees that a temporary address will be valid for at least + // 2hrs if the SLAAC prefix is valid for at least that time. + MinMaxTempAddrValidLifetime = 2 * time.Hour ) // DHCPv6ConfigurationFromNDPRA is a configuration available via DHCPv6 that an @@ -138,9 +199,11 @@ var ( type DHCPv6ConfigurationFromNDPRA int const ( + _ DHCPv6ConfigurationFromNDPRA = iota + // DHCPv6NoConfiguration indicates that no configurations are available via // DHCPv6. - DHCPv6NoConfiguration DHCPv6ConfigurationFromNDPRA = iota + DHCPv6NoConfiguration // DHCPv6ManagedAddress indicates that addresses are available via DHCPv6. // @@ -254,9 +317,6 @@ type NDPDispatcher interface { // OnDHCPv6Configuration will be called with an updated configuration that is // available via DHCPv6 for a specified NIC. // - // NDPDispatcher assumes that the initial configuration available by DHCPv6 is - // DHCPv6NoConfiguration. - // // This function is not permitted to block indefinitely. It must not // call functions on the stack itself. OnDHCPv6Configuration(tcpip.NICID, DHCPv6ConfigurationFromNDPRA) @@ -324,35 +384,49 @@ type NDPConfigurations struct { // alternative addresses (e.g. IIDs based on the modified EUI64 of a NIC's // MAC address), then no attempt will be made to resolve the conflict. AutoGenAddressConflictRetries uint8 + + // AutoGenTempGlobalAddresses determines whether or not temporary SLAAC + // addresses will be generated for a NIC as part of SLAAC privacy extensions, + // RFC 4941. + // + // Ignored if AutoGenGlobalAddresses is false. + AutoGenTempGlobalAddresses bool + + // MaxTempAddrValidLifetime is the maximum valid lifetime for temporary + // SLAAC addresses. + MaxTempAddrValidLifetime time.Duration + + // MaxTempAddrPreferredLifetime is the maximum preferred lifetime for + // temporary SLAAC addresses. + MaxTempAddrPreferredLifetime time.Duration + + // RegenAdvanceDuration is the duration before the deprecation of a temporary + // address when a new address will be generated. + RegenAdvanceDuration time.Duration } // DefaultNDPConfigurations returns an NDPConfigurations populated with // default values. func DefaultNDPConfigurations() NDPConfigurations { return NDPConfigurations{ - DupAddrDetectTransmits: defaultDupAddrDetectTransmits, - RetransmitTimer: defaultRetransmitTimer, - MaxRtrSolicitations: defaultMaxRtrSolicitations, - RtrSolicitationInterval: defaultRtrSolicitationInterval, - MaxRtrSolicitationDelay: defaultMaxRtrSolicitationDelay, - HandleRAs: defaultHandleRAs, - DiscoverDefaultRouters: defaultDiscoverDefaultRouters, - DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, - AutoGenGlobalAddresses: defaultAutoGenGlobalAddresses, + DupAddrDetectTransmits: defaultDupAddrDetectTransmits, + RetransmitTimer: defaultRetransmitTimer, + MaxRtrSolicitations: defaultMaxRtrSolicitations, + RtrSolicitationInterval: defaultRtrSolicitationInterval, + MaxRtrSolicitationDelay: defaultMaxRtrSolicitationDelay, + HandleRAs: defaultHandleRAs, + DiscoverDefaultRouters: defaultDiscoverDefaultRouters, + DiscoverOnLinkPrefixes: defaultDiscoverOnLinkPrefixes, + AutoGenGlobalAddresses: defaultAutoGenGlobalAddresses, + AutoGenTempGlobalAddresses: defaultAutoGenTempGlobalAddresses, + MaxTempAddrValidLifetime: defaultMaxTempAddrValidLifetime, + MaxTempAddrPreferredLifetime: defaultMaxTempAddrPreferredLifetime, + RegenAdvanceDuration: defaultRegenAdvanceDuration, } } // validate modifies an NDPConfigurations with valid values. If invalid values // are present in c, the corresponding default values will be used instead. -// -// If RetransmitTimer is less than minimumRetransmitTimer, then a value of -// defaultRetransmitTimer will be used. -// -// If RtrSolicitationInterval is less than minimumRtrSolicitationInterval, then -// a value of defaultRtrSolicitationInterval will be used. -// -// If MaxRtrSolicitationDelay is less than minimumMaxRtrSolicitationDelay, then -// a value of defaultMaxRtrSolicitationDelay will be used. func (c *NDPConfigurations) validate() { if c.RetransmitTimer < minimumRetransmitTimer { c.RetransmitTimer = defaultRetransmitTimer @@ -365,6 +439,18 @@ func (c *NDPConfigurations) validate() { if c.MaxRtrSolicitationDelay < minimumMaxRtrSolicitationDelay { c.MaxRtrSolicitationDelay = defaultMaxRtrSolicitationDelay } + + if c.MaxTempAddrValidLifetime < MinMaxTempAddrValidLifetime { + c.MaxTempAddrValidLifetime = MinMaxTempAddrValidLifetime + } + + if c.MaxTempAddrPreferredLifetime < MinMaxTempAddrPreferredLifetime || c.MaxTempAddrPreferredLifetime > c.MaxTempAddrValidLifetime { + c.MaxTempAddrPreferredLifetime = MinMaxTempAddrPreferredLifetime + } + + if c.RegenAdvanceDuration < minRegenAdvanceDuration { + c.RegenAdvanceDuration = minRegenAdvanceDuration + } } // ndpState is the per-interface NDP state. @@ -394,6 +480,14 @@ type ndpState struct { // The last learned DHCPv6 configuration from an NDP RA. dhcpv6Configuration DHCPv6ConfigurationFromNDPRA + + // temporaryIIDHistory is the history value used to generate a new temporary + // IID. + temporaryIIDHistory [header.IIDSize]byte + + // temporaryAddressDesyncFactor is the preferred lifetime's desync factor for + // temporary SLAAC addresses. + temporaryAddressDesyncFactor time.Duration } // dadState holds the Duplicate Address Detection timer and channel to signal @@ -414,7 +508,7 @@ type dadState struct { type defaultRouterState struct { // Timer to invalidate the default router. // - // May not be nil. + // Must not be nil. invalidationTimer *tcpip.CancellableTimer } @@ -424,20 +518,48 @@ type defaultRouterState struct { type onLinkPrefixState struct { // Timer to invalidate the on-link prefix. // - // May not be nil. + // Must not be nil. invalidationTimer *tcpip.CancellableTimer } +// tempSLAACAddrState holds state associated with a temporary SLAAC address. +type tempSLAACAddrState struct { + // Timer to deprecate the temporary SLAAC address. + // + // Must not be nil. + deprecationTimer *tcpip.CancellableTimer + + // Timer to invalidate the temporary SLAAC address. + // + // Must not be nil. + invalidationTimer *tcpip.CancellableTimer + + // Timer to regenerate the temporary SLAAC address. + // + // Must not be nil. + regenTimer *tcpip.CancellableTimer + + createdAt time.Time + + // The address's endpoint. + // + // Must not be nil. + ref *referencedNetworkEndpoint + + // Has a new temporary SLAAC address already been regenerated? + regenerated bool +} + // slaacPrefixState holds state associated with a SLAAC prefix. type slaacPrefixState struct { // Timer to deprecate the prefix. // - // May not be nil. + // Must not be nil. deprecationTimer *tcpip.CancellableTimer // Timer to invalidate the prefix. // - // May not be nil. + // Must not be nil. invalidationTimer *tcpip.CancellableTimer // Nonzero only when the address is not valid forever. @@ -446,19 +568,34 @@ type slaacPrefixState struct { // Nonzero only when the address is not preferred forever. preferredUntil time.Time - // The prefix's permanent address endpoint. - // - // May only be nil when a SLAAC address is being (re-)generated. Otherwise, - // must not be nil as all SLAAC prefixes must have a SLAAC address. - ref *referencedNetworkEndpoint + // State associated with the stable address generated for the prefix. + stableAddr struct { + // The address's endpoint. + // + // May only be nil when the address is being (re-)generated. Otherwise, + // must not be nil as all SLAAC prefixes must have a stable address. + ref *referencedNetworkEndpoint + + // The number of times an address has been generated locally where the NIC + // already had the generated address. + localGenerationFailures uint8 + } - // The number of times a permanent address has been generated for the prefix. + // The temporary (short-lived) addresses generated for the SLAAC prefix. + tempAddrs map[tcpip.Address]tempSLAACAddrState + + // The next two fields are used by both stable and temporary addresses + // generated for a SLAAC prefix. This is safe as only 1 address will be + // in the generation and DAD process at any time. That is, no two addresses + // will be generated at the same time for a given SLAAC prefix. + + // The number of times an address has been generated and added to the NIC. // // Addresses may be regenerated in reseponse to a DAD conflicts. generationAttempts uint8 - // The maximum number of times to attempt regeneration of a permanent SLAAC - // address in response to DAD conflicts. + // The maximum number of times to attempt regeneration of a SLAAC address + // in response to DAD conflicts. maxGenerationAttempts uint8 } @@ -536,10 +673,10 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref } ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() if done { // If we reach this point, it means that DAD was stopped after we released // the NIC's read lock and before we obtained the write lock. - ndp.nic.mu.Unlock() return } @@ -551,8 +688,6 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref // schedule the next DAD timer. remaining-- timer.Reset(ndp.nic.stack.ndpConfigs.RetransmitTimer) - - ndp.nic.mu.Unlock() return } @@ -560,15 +695,18 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref // the last NDP NS. Either way, clean up addr's DAD state and let the // integrator know DAD has completed. delete(ndp.dad, addr) - ndp.nic.mu.Unlock() - - if err != nil { - log.Printf("ndpdad: error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, ndp.nic.ID(), err) - } if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, dadDone, err) } + + // If DAD resolved for a stable SLAAC address, attempt generation of a + // temporary SLAAC address. + if dadDone && ref.configType == slaac { + // Reset the generation attempts counter as we are starting the generation + // of a new address for the SLAAC prefix. + ndp.regenerateTempSLAACAddr(ref.addrWithPrefix().Subnet(), true /* resetGenAttempts */) + } }) ndp.dad[addr] = dadState{ @@ -953,9 +1091,10 @@ func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInform prefix := pi.Subnet() // Check if we already maintain SLAAC state for prefix. - if _, ok := ndp.slaacPrefixes[prefix]; ok { + if state, ok := ndp.slaacPrefixes[prefix]; ok { // As per RFC 4862 section 5.5.3.e, refresh prefix's SLAAC lifetimes. - ndp.refreshSLAACPrefixLifetimes(prefix, pl, vl) + ndp.refreshSLAACPrefixLifetimes(prefix, &state, pl, vl) + ndp.slaacPrefixes[prefix] = state return } @@ -996,7 +1135,7 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) { panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for the deprecated SLAAC prefix %s", prefix)) } - ndp.deprecateSLAACAddress(state.ref) + ndp.deprecateSLAACAddress(state.stableAddr.ref) }), invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() { state, ok := ndp.slaacPrefixes[prefix] @@ -1006,6 +1145,7 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) { ndp.invalidateSLAACPrefix(prefix, state) }), + tempAddrs: make(map[tcpip.Address]tempSLAACAddrState), maxGenerationAttempts: ndp.configs.AutoGenAddressConflictRetries + 1, } @@ -1035,9 +1175,44 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) { state.validUntil = now.Add(vl) } + // If the address is assigned (DAD resolved), generate a temporary address. + if state.stableAddr.ref.getKind() == permanent { + // Reset the generation attempts counter as we are starting the generation + // of a new address for the SLAAC prefix. + ndp.generateTempSLAACAddr(prefix, &state, true /* resetGenAttempts */) + } + ndp.slaacPrefixes[prefix] = state } +// addSLAACAddr adds a SLAAC address to the NIC. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) addSLAACAddr(addr tcpip.AddressWithPrefix, configType networkEndpointConfigType, deprecated bool) *referencedNetworkEndpoint { + // Inform the integrator that we have a new SLAAC address. + ndpDisp := ndp.nic.stack.ndpDisp + if ndpDisp == nil { + return nil + } + + if !ndpDisp.OnAutoGenAddress(ndp.nic.ID(), addr) { + // Informed by the integrator not to add the address. + return nil + } + + protocolAddr := tcpip.ProtocolAddress{ + Protocol: header.IPv6ProtocolNumber, + AddressWithPrefix: addr, + } + + ref, err := ndp.nic.addAddressLocked(protocolAddr, FirstPrimaryEndpoint, permanent, configType, deprecated) + if err != nil { + panic(fmt.Sprintf("ndp: error when adding SLAAC address %+v: %s", protocolAddr, err)) + } + + return ref +} + // generateSLAACAddr generates a SLAAC address for prefix. // // Returns true if an address was successfully generated. @@ -1046,7 +1221,7 @@ func (ndp *ndpState) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) { // // The NIC that ndp belongs to MUST be locked. func (ndp *ndpState) generateSLAACAddr(prefix tcpip.Subnet, state *slaacPrefixState) bool { - if r := state.ref; r != nil { + if r := state.stableAddr.ref; r != nil { panic(fmt.Sprintf("ndp: SLAAC prefix %s already has a permenant address %s", prefix, r.addrWithPrefix())) } @@ -1056,68 +1231,67 @@ func (ndp *ndpState) generateSLAACAddr(prefix tcpip.Subnet, state *slaacPrefixSt return false } + var generatedAddr tcpip.AddressWithPrefix addrBytes := []byte(prefix.ID()) - if oIID := ndp.nic.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { - addrBytes = header.AppendOpaqueInterfaceIdentifier( - addrBytes[:header.IIDOffsetInIPv6Address], - prefix, - oIID.NICNameFromID(ndp.nic.ID(), ndp.nic.name), - state.generationAttempts, - oIID.SecretKey, - ) - } else if state.generationAttempts == 0 { - // Only attempt to generate an interface-specific IID if we have a valid - // link address. - // - // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by - // LinkEndpoint.LinkAddress) before reaching this point. - linkAddr := ndp.nic.linkEP.LinkAddress() - if !header.IsValidUnicastEthernetAddress(linkAddr) { + + for i := 0; ; i++ { + // If we were unable to generate an address after the maximum SLAAC address + // local regeneration attempts, do nothing further. + if i == maxSLAACAddrLocalRegenAttempts { return false } - // Generate an address within prefix from the modified EUI-64 of ndp's NIC's - // Ethernet MAC address. - header.EthernetAdddressToModifiedEUI64IntoBuf(linkAddr, addrBytes[header.IIDOffsetInIPv6Address:]) - } else { - // We have no way to regenerate an address when addresses are not generated - // with opaque IIDs. - return false - } + dadCounter := state.generationAttempts + state.stableAddr.localGenerationFailures + if oIID := ndp.nic.stack.opaqueIIDOpts; oIID.NICNameFromID != nil { + addrBytes = header.AppendOpaqueInterfaceIdentifier( + addrBytes[:header.IIDOffsetInIPv6Address], + prefix, + oIID.NICNameFromID(ndp.nic.ID(), ndp.nic.name), + dadCounter, + oIID.SecretKey, + ) + } else if dadCounter == 0 { + // Modified-EUI64 based IIDs have no way to resolve DAD conflicts, so if + // the DAD counter is non-zero, we cannot use this method. + // + // Only attempt to generate an interface-specific IID if we have a valid + // link address. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + linkAddr := ndp.nic.linkEP.LinkAddress() + if !header.IsValidUnicastEthernetAddress(linkAddr) { + return false + } - generatedAddr := tcpip.ProtocolAddress{ - Protocol: header.IPv6ProtocolNumber, - AddressWithPrefix: tcpip.AddressWithPrefix{ + // Generate an address within prefix from the modified EUI-64 of ndp's + // NIC's Ethernet MAC address. + header.EthernetAdddressToModifiedEUI64IntoBuf(linkAddr, addrBytes[header.IIDOffsetInIPv6Address:]) + } else { + // We have no way to regenerate an address in response to an address + // conflict when addresses are not generated with opaque IIDs. + return false + } + + generatedAddr = tcpip.AddressWithPrefix{ Address: tcpip.Address(addrBytes), PrefixLen: validPrefixLenForAutoGen, - }, - } - - // If the nic already has this address, do nothing further. - if ndp.nic.hasPermanentAddrLocked(generatedAddr.AddressWithPrefix.Address) { - return false - } + } - // Inform the integrator that we have a new SLAAC address. - ndpDisp := ndp.nic.stack.ndpDisp - if ndpDisp == nil { - return false - } + if !ndp.nic.hasPermanentAddrLocked(generatedAddr.Address) { + break + } - if !ndpDisp.OnAutoGenAddress(ndp.nic.ID(), generatedAddr.AddressWithPrefix) { - // Informed by the integrator not to add the address. - return false + state.stableAddr.localGenerationFailures++ } - deprecated := time.Since(state.preferredUntil) >= 0 - ref, err := ndp.nic.addAddressLocked(generatedAddr, FirstPrimaryEndpoint, permanent, slaac, deprecated) - if err != nil { - panic(fmt.Sprintf("ndp: error when adding address %+v: %s", generatedAddr, err)) + if ref := ndp.addSLAACAddr(generatedAddr, slaac, time.Since(state.preferredUntil) >= 0 /* deprecated */); ref != nil { + state.stableAddr.ref = ref + state.generationAttempts++ + return true } - state.generationAttempts++ - state.ref = ref - return true + return false } // regenerateSLAACAddr regenerates an address for a SLAAC prefix. @@ -1143,24 +1317,180 @@ func (ndp *ndpState) regenerateSLAACAddr(prefix tcpip.Subnet) { ndp.invalidateSLAACPrefix(prefix, state) } -// refreshSLAACPrefixLifetimes refreshes the lifetimes of a SLAAC prefix. +// generateTempSLAACAddr generates a new temporary SLAAC address. // -// pl is the new preferred lifetime. vl is the new valid lifetime. +// If resetGenAttempts is true, the prefix's generation counter will be reset. +// +// Returns true if a new address was generated. +func (ndp *ndpState) generateTempSLAACAddr(prefix tcpip.Subnet, prefixState *slaacPrefixState, resetGenAttempts bool) bool { + // Are we configured to auto-generate new temporary global addresses for the + // prefix? + if !ndp.configs.AutoGenTempGlobalAddresses || prefix == header.IPv6LinkLocalPrefix.Subnet() { + return false + } + + if resetGenAttempts { + prefixState.generationAttempts = 0 + prefixState.maxGenerationAttempts = ndp.configs.AutoGenAddressConflictRetries + 1 + } + + // If we have already reached the maximum address generation attempts for the + // prefix, do not generate another address. + if prefixState.generationAttempts == prefixState.maxGenerationAttempts { + return false + } + + stableAddr := prefixState.stableAddr.ref.ep.ID().LocalAddress + now := time.Now() + + // As per RFC 4941 section 3.3 step 4, the valid lifetime of a temporary + // address is the lower of the valid lifetime of the stable address or the + // maximum temporary address valid lifetime. + vl := ndp.configs.MaxTempAddrValidLifetime + if prefixState.validUntil != (time.Time{}) { + if prefixVL := prefixState.validUntil.Sub(now); vl > prefixVL { + vl = prefixVL + } + } + + if vl <= 0 { + // Cannot create an address without a valid lifetime. + return false + } + + // As per RFC 4941 section 3.3 step 4, the preferred lifetime of a temporary + // address is the lower of the preferred lifetime of the stable address or the + // maximum temporary address preferred lifetime - the temporary address desync + // factor. + pl := ndp.configs.MaxTempAddrPreferredLifetime - ndp.temporaryAddressDesyncFactor + if prefixState.preferredUntil != (time.Time{}) { + if prefixPL := prefixState.preferredUntil.Sub(now); pl > prefixPL { + // Respect the preferred lifetime of the prefix, as per RFC 4941 section + // 3.3 step 4. + pl = prefixPL + } + } + + // As per RFC 4941 section 3.3 step 5, a temporary address is created only if + // the calculated preferred lifetime is greater than the advance regeneration + // duration. In particular, we MUST NOT create a temporary address with a zero + // Preferred Lifetime. + if pl <= ndp.configs.RegenAdvanceDuration { + return false + } + + // Attempt to generate a new address that is not already assigned to the NIC. + var generatedAddr tcpip.AddressWithPrefix + for i := 0; ; i++ { + // If we were unable to generate an address after the maximum SLAAC address + // local regeneration attempts, do nothing further. + if i == maxSLAACAddrLocalRegenAttempts { + return false + } + + generatedAddr = header.GenerateTempIPv6SLAACAddr(ndp.temporaryIIDHistory[:], stableAddr) + if !ndp.nic.hasPermanentAddrLocked(generatedAddr.Address) { + break + } + } + + // As per RFC RFC 4941 section 3.3 step 5, we MUST NOT create a temporary + // address with a zero preferred lifetime. The checks above ensure this + // so we know the address is not deprecated. + ref := ndp.addSLAACAddr(generatedAddr, slaacTemp, false /* deprecated */) + if ref == nil { + return false + } + + state := tempSLAACAddrState{ + deprecationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() { + prefixState, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to deprecate temporary address %s", prefix, generatedAddr)) + } + + tempAddrState, ok := prefixState.tempAddrs[generatedAddr.Address] + if !ok { + panic(fmt.Sprintf("ndp: must have a tempAddr entry to deprecate temporary address %s", generatedAddr)) + } + + ndp.deprecateSLAACAddress(tempAddrState.ref) + }), + invalidationTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() { + prefixState, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to invalidate temporary address %s", prefix, generatedAddr)) + } + + tempAddrState, ok := prefixState.tempAddrs[generatedAddr.Address] + if !ok { + panic(fmt.Sprintf("ndp: must have a tempAddr entry to invalidate temporary address %s", generatedAddr)) + } + + ndp.invalidateTempSLAACAddr(prefixState.tempAddrs, generatedAddr.Address, tempAddrState) + }), + regenTimer: tcpip.NewCancellableTimer(&ndp.nic.mu, func() { + prefixState, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for %s to regenerate temporary address after %s", prefix, generatedAddr)) + } + + tempAddrState, ok := prefixState.tempAddrs[generatedAddr.Address] + if !ok { + panic(fmt.Sprintf("ndp: must have a tempAddr entry to regenerate temporary address after %s", generatedAddr)) + } + + // If an address has already been regenerated for this address, don't + // regenerate another address. + if tempAddrState.regenerated { + return + } + + // Reset the generation attempts counter as we are starting the generation + // of a new address for the SLAAC prefix. + tempAddrState.regenerated = ndp.generateTempSLAACAddr(prefix, &prefixState, true /* resetGenAttempts */) + prefixState.tempAddrs[generatedAddr.Address] = tempAddrState + ndp.slaacPrefixes[prefix] = prefixState + }), + createdAt: now, + ref: ref, + } + + state.deprecationTimer.Reset(pl) + state.invalidationTimer.Reset(vl) + state.regenTimer.Reset(pl - ndp.configs.RegenAdvanceDuration) + + prefixState.generationAttempts++ + prefixState.tempAddrs[generatedAddr.Address] = state + + return true +} + +// regenerateTempSLAACAddr regenerates a temporary address for a SLAAC prefix. // // The NIC that ndp belongs to MUST be locked. -func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, pl, vl time.Duration) { - prefixState, ok := ndp.slaacPrefixes[prefix] +func (ndp *ndpState) regenerateTempSLAACAddr(prefix tcpip.Subnet, resetGenAttempts bool) { + state, ok := ndp.slaacPrefixes[prefix] if !ok { - panic(fmt.Sprintf("ndp: SLAAC prefix state not found to refresh lifetimes for %s", prefix)) + panic(fmt.Sprintf("ndp: SLAAC prefix state not found to regenerate temporary address for %s", prefix)) } - defer func() { ndp.slaacPrefixes[prefix] = prefixState }() + ndp.generateTempSLAACAddr(prefix, &state, resetGenAttempts) + ndp.slaacPrefixes[prefix] = state +} + +// refreshSLAACPrefixLifetimes refreshes the lifetimes of a SLAAC prefix. +// +// pl is the new preferred lifetime. vl is the new valid lifetime. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, prefixState *slaacPrefixState, pl, vl time.Duration) { // If the preferred lifetime is zero, then the prefix should be deprecated. deprecated := pl == 0 if deprecated { - ndp.deprecateSLAACAddress(prefixState.ref) + ndp.deprecateSLAACAddress(prefixState.stableAddr.ref) } else { - prefixState.ref.deprecated = false + prefixState.stableAddr.ref.deprecated = false } // If prefix was preferred for some finite lifetime before, stop the @@ -1190,36 +1520,118 @@ func (ndp *ndpState) refreshSLAACPrefixLifetimes(prefix tcpip.Subnet, pl, vl tim // // 3) Otherwise, reset the valid lifetime of the prefix to 2 hours. - // Handle the infinite valid lifetime separately as we do not keep a timer in - // this case. if vl >= header.NDPInfiniteLifetime { + // Handle the infinite valid lifetime separately as we do not keep a timer + // in this case. prefixState.invalidationTimer.StopLocked() prefixState.validUntil = time.Time{} - return - } + } else { + var effectiveVl time.Duration + var rl time.Duration - var effectiveVl time.Duration - var rl time.Duration + // If the prefix was originally set to be valid forever, assume the + // remaining time to be the maximum possible value. + if prefixState.validUntil == (time.Time{}) { + rl = header.NDPInfiniteLifetime + } else { + rl = time.Until(prefixState.validUntil) + } - // If the prefix was originally set to be valid forever, assume the remaining - // time to be the maximum possible value. - if prefixState.validUntil == (time.Time{}) { - rl = header.NDPInfiniteLifetime - } else { - rl = time.Until(prefixState.validUntil) + if vl > MinPrefixInformationValidLifetimeForUpdate || vl > rl { + effectiveVl = vl + } else if rl > MinPrefixInformationValidLifetimeForUpdate { + effectiveVl = MinPrefixInformationValidLifetimeForUpdate + } + + if effectiveVl != 0 { + prefixState.invalidationTimer.StopLocked() + prefixState.invalidationTimer.Reset(effectiveVl) + prefixState.validUntil = now.Add(effectiveVl) + } } - if vl > MinPrefixInformationValidLifetimeForUpdate || vl > rl { - effectiveVl = vl - } else if rl <= MinPrefixInformationValidLifetimeForUpdate { + // If DAD is not yet complete on the stable address, there is no need to do + // work with temporary addresses. + if prefixState.stableAddr.ref.getKind() != permanent { return - } else { - effectiveVl = MinPrefixInformationValidLifetimeForUpdate } - prefixState.invalidationTimer.StopLocked() - prefixState.invalidationTimer.Reset(effectiveVl) - prefixState.validUntil = now.Add(effectiveVl) + // Note, we do not need to update the entries in the temporary address map + // after updating the timers because the timers are held as pointers. + var regenForAddr tcpip.Address + allAddressesRegenerated := true + for tempAddr, tempAddrState := range prefixState.tempAddrs { + // As per RFC 4941 section 3.3 step 4, the valid lifetime of a temporary + // address is the lower of the valid lifetime of the stable address or the + // maximum temporary address valid lifetime. Note, the valid lifetime of a + // temporary address is relative to the address's creation time. + validUntil := tempAddrState.createdAt.Add(ndp.configs.MaxTempAddrValidLifetime) + if prefixState.validUntil != (time.Time{}) && validUntil.Sub(prefixState.validUntil) > 0 { + validUntil = prefixState.validUntil + } + + // If the address is no longer valid, invalidate it immediately. Otherwise, + // reset the invalidation timer. + newValidLifetime := validUntil.Sub(now) + if newValidLifetime <= 0 { + ndp.invalidateTempSLAACAddr(prefixState.tempAddrs, tempAddr, tempAddrState) + continue + } + tempAddrState.invalidationTimer.StopLocked() + tempAddrState.invalidationTimer.Reset(newValidLifetime) + + // As per RFC 4941 section 3.3 step 4, the preferred lifetime of a temporary + // address is the lower of the preferred lifetime of the stable address or + // the maximum temporary address preferred lifetime - the temporary address + // desync factor. Note, the preferred lifetime of a temporary address is + // relative to the address's creation time. + preferredUntil := tempAddrState.createdAt.Add(ndp.configs.MaxTempAddrPreferredLifetime - ndp.temporaryAddressDesyncFactor) + if prefixState.preferredUntil != (time.Time{}) && preferredUntil.Sub(prefixState.preferredUntil) > 0 { + preferredUntil = prefixState.preferredUntil + } + + // If the address is no longer preferred, deprecate it immediately. + // Otherwise, reset the deprecation timer. + newPreferredLifetime := preferredUntil.Sub(now) + tempAddrState.deprecationTimer.StopLocked() + if newPreferredLifetime <= 0 { + ndp.deprecateSLAACAddress(tempAddrState.ref) + } else { + tempAddrState.ref.deprecated = false + tempAddrState.deprecationTimer.Reset(newPreferredLifetime) + } + + tempAddrState.regenTimer.StopLocked() + if tempAddrState.regenerated { + } else { + allAddressesRegenerated = false + + if newPreferredLifetime <= ndp.configs.RegenAdvanceDuration { + // The new preferred lifetime is less than the advance regeneration + // duration so regenerate an address for this temporary address + // immediately after we finish iterating over the temporary addresses. + regenForAddr = tempAddr + } else { + tempAddrState.regenTimer.Reset(newPreferredLifetime - ndp.configs.RegenAdvanceDuration) + } + } + } + + // Generate a new temporary address if all of the existing temporary addresses + // have been regenerated, or we need to immediately regenerate an address + // due to an update in preferred lifetime. + // + // If each temporay address has already been regenerated, no new temporary + // address will be generated. To ensure continuation of temporary SLAAC + // addresses, we manually try to regenerate an address here. + if len(regenForAddr) != 0 || allAddressesRegenerated { + // Reset the generation attempts counter as we are starting the generation + // of a new address for the SLAAC prefix. + if state, ok := prefixState.tempAddrs[regenForAddr]; ndp.generateTempSLAACAddr(prefix, prefixState, true /* resetGenAttempts */) && ok { + state.regenerated = true + prefixState.tempAddrs[regenForAddr] = state + } + } } // deprecateSLAACAddress marks ref as deprecated and notifies the stack's NDP @@ -1243,11 +1655,11 @@ func (ndp *ndpState) deprecateSLAACAddress(ref *referencedNetworkEndpoint) { // // The NIC that ndp belongs to MUST be locked. func (ndp *ndpState) invalidateSLAACPrefix(prefix tcpip.Subnet, state slaacPrefixState) { - if r := state.ref; r != nil { + if r := state.stableAddr.ref; r != nil { // Since we are already invalidating the prefix, do not invalidate the // prefix when removing the address. - if err := ndp.nic.removePermanentIPv6EndpointLocked(r, false /* allowSLAACPrefixInvalidation */); err != nil { - panic(fmt.Sprintf("ndp: removePermanentIPv6EndpointLocked(%s, false): %s", r.addrWithPrefix(), err)) + if err := ndp.nic.removePermanentIPv6EndpointLocked(r, false /* allowSLAACInvalidation */); err != nil { + panic(fmt.Sprintf("ndp: error removing stable SLAAC address %s: %s", r.addrWithPrefix(), err)) } } @@ -1265,14 +1677,14 @@ func (ndp *ndpState) cleanupSLAACAddrResourcesAndNotify(addr tcpip.AddressWithPr prefix := addr.Subnet() state, ok := ndp.slaacPrefixes[prefix] - if !ok || state.ref == nil || addr.Address != state.ref.ep.ID().LocalAddress { + if !ok || state.stableAddr.ref == nil || addr.Address != state.stableAddr.ref.ep.ID().LocalAddress { return } if !invalidatePrefix { // If the prefix is not being invalidated, disassociate the address from the // prefix and do nothing further. - state.ref = nil + state.stableAddr.ref = nil ndp.slaacPrefixes[prefix] = state return } @@ -1286,11 +1698,68 @@ func (ndp *ndpState) cleanupSLAACAddrResourcesAndNotify(addr tcpip.AddressWithPr // // The NIC that ndp belongs to MUST be locked. func (ndp *ndpState) cleanupSLAACPrefixResources(prefix tcpip.Subnet, state slaacPrefixState) { + // Invalidate all temporary addresses. + for tempAddr, tempAddrState := range state.tempAddrs { + ndp.invalidateTempSLAACAddr(state.tempAddrs, tempAddr, tempAddrState) + } + + state.stableAddr.ref = nil state.deprecationTimer.StopLocked() state.invalidationTimer.StopLocked() delete(ndp.slaacPrefixes, prefix) } +// invalidateTempSLAACAddr invalidates a temporary SLAAC address. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) invalidateTempSLAACAddr(tempAddrs map[tcpip.Address]tempSLAACAddrState, tempAddr tcpip.Address, tempAddrState tempSLAACAddrState) { + // Since we are already invalidating the address, do not invalidate the + // address when removing the address. + if err := ndp.nic.removePermanentIPv6EndpointLocked(tempAddrState.ref, false /* allowSLAACInvalidation */); err != nil { + panic(fmt.Sprintf("error removing temporary SLAAC address %s: %s", tempAddrState.ref.addrWithPrefix(), err)) + } + + ndp.cleanupTempSLAACAddrResources(tempAddrs, tempAddr, tempAddrState) +} + +// cleanupTempSLAACAddrResourcesAndNotify cleans up an invalidated temporary +// SLAAC address's resources from ndp. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) cleanupTempSLAACAddrResourcesAndNotify(addr tcpip.AddressWithPrefix, invalidateAddr bool) { + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnAutoGenAddressInvalidated(ndp.nic.ID(), addr) + } + + if !invalidateAddr { + return + } + + prefix := addr.Subnet() + state, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry to clean up temp addr %s resources", addr)) + } + + tempAddrState, ok := state.tempAddrs[addr.Address] + if !ok { + panic(fmt.Sprintf("ndp: must have a tempAddr entry to clean up temp addr %s resources", addr)) + } + + ndp.cleanupTempSLAACAddrResources(state.tempAddrs, addr.Address, tempAddrState) +} + +// cleanupTempSLAACAddrResourcesAndNotify cleans up a temporary SLAAC address's +// timers and entry. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) cleanupTempSLAACAddrResources(tempAddrs map[tcpip.Address]tempSLAACAddrState, tempAddr tcpip.Address, tempAddrState tempSLAACAddrState) { + tempAddrState.deprecationTimer.StopLocked() + tempAddrState.invalidationTimer.StopLocked() + tempAddrState.regenTimer.StopLocked() + delete(tempAddrs, tempAddr) +} + // cleanupState cleans up ndp's state. // // If hostOnly is true, then only host-specific state will be cleaned up. @@ -1338,6 +1807,8 @@ func (ndp *ndpState) cleanupState(hostOnly bool) { if got := len(ndp.defaultRouters); got != 0 { panic(fmt.Sprintf("ndp: still have discovered default routers after cleaning up; found = %d", got)) } + + ndp.dhcpv6Configuration = 0 } // startSolicitingRouters starts soliciting routers, as per RFC 4861 section @@ -1450,3 +1921,13 @@ func (ndp *ndpState) stopSolicitingRouters() { ndp.rtrSolicitTimer.Stop() ndp.rtrSolicitTimer = nil } + +// initializeTempAddrState initializes state related to temporary SLAAC +// addresses. +func (ndp *ndpState) initializeTempAddrState() { + header.InitialTempIID(ndp.temporaryIIDHistory[:], ndp.nic.stack.tempIIDSeed, ndp.nic.ID()) + + if MaxDesyncFactor != 0 { + ndp.temporaryAddressDesyncFactor = time.Duration(rand.Int63n(int64(MaxDesyncFactor))) + } +} |