diff options
Diffstat (limited to 'pkg/tcpip/stack/ndp.go')
| -rw-r--r-- | pkg/tcpip/stack/ndp.go | 1910 |
1 files changed, 1781 insertions, 129 deletions
diff --git a/pkg/tcpip/stack/ndp.go b/pkg/tcpip/stack/ndp.go index 03ddebdbd..97ca00d16 100644 --- a/pkg/tcpip/stack/ndp.go +++ b/pkg/tcpip/stack/ndp.go @@ -17,6 +17,7 @@ package stack import ( "fmt" "log" + "math/rand" "time" "gvisor.dev/gvisor/pkg/tcpip" @@ -32,39 +33,277 @@ const ( // Default = 1 (from RFC 4862 section 5.1) defaultDupAddrDetectTransmits = 1 - // defaultRetransmitTimer is the default amount of time to wait between - // sending NDP Neighbor solicitation messages. + // defaultMaxRtrSolicitations is the default number of Router + // Solicitation messages to send when a NIC becomes enabled. // - // Default = 1s (from RFC 4861 section 10). - defaultRetransmitTimer = time.Second + // Default = 3 (from RFC 4861 section 10). + defaultMaxRtrSolicitations = 3 - // minimumRetransmitTimer is the minimum amount of time to wait between - // sending NDP Neighbor solicitation messages. Note, RFC 4861 does - // not impose a minimum Retransmit Timer, but we do here to make sure - // the messages are not sent all at once. We also come to this value - // because in the RetransmitTimer field of a Router Advertisement, a - // value of 0 means unspecified, so the smallest valid value is 1. - // Note, the unit of the RetransmitTimer field in the Router - // Advertisement is milliseconds. + // defaultRtrSolicitationInterval is the default amount of time between + // sending Router Solicitation messages. // - // Min = 1ms. - minimumRetransmitTimer = time.Millisecond + // Default = 4s (from 4861 section 10). + defaultRtrSolicitationInterval = 4 * time.Second + + // defaultMaxRtrSolicitationDelay is the default maximum amount of time + // to wait before sending the first Router Solicitation message. + // + // Default = 1s (from 4861 section 10). + defaultMaxRtrSolicitationDelay = time.Second + + // defaultHandleRAs is the default configuration for whether or not to + // handle incoming Router Advertisements as a host. + defaultHandleRAs = true + + // defaultDiscoverDefaultRouters is the default configuration for + // whether or not to discover default routers from incoming Router + // Advertisements, as a host. + defaultDiscoverDefaultRouters = true + + // defaultDiscoverOnLinkPrefixes is the default configuration for + // whether or not to discover on-link prefixes from incoming Router + // Advertisements' Prefix Information option, as a host. + defaultDiscoverOnLinkPrefixes = true + + // defaultAutoGenGlobalAddresses is the default configuration for + // whether or not to generate global IPv6 addresses in response to + // receiving a new Prefix Information option with its Autonomous + // Address AutoConfiguration flag set, as a host. + // + // Default = true. + defaultAutoGenGlobalAddresses = true + + // minimumRtrSolicitationInterval is the minimum amount of time to wait + // between sending Router Solicitation messages. This limit is imposed + // to make sure that Router Solicitation messages are not sent all at + // once, defeating the purpose of sending the initial few messages. + minimumRtrSolicitationInterval = 500 * time.Millisecond + + // minimumMaxRtrSolicitationDelay is the minimum amount of time to wait + // before sending the first Router Solicitation message. It is 0 because + // we cannot have a negative delay. + minimumMaxRtrSolicitationDelay = 0 + + // MaxDiscoveredDefaultRouters is the maximum number of discovered + // default routers. The stack should stop discovering new routers after + // discovering MaxDiscoveredDefaultRouters routers. + // + // This value MUST be at minimum 2 as per RFC 4861 section 6.3.4, and + // SHOULD be more. + MaxDiscoveredDefaultRouters = 10 + + // MaxDiscoveredOnLinkPrefixes is the maximum number of discovered + // on-link prefixes. The stack should stop discovering new on-link + // prefixes after discovering MaxDiscoveredOnLinkPrefixes on-link + // prefixes. + MaxDiscoveredOnLinkPrefixes = 10 + + // validPrefixLenForAutoGen is the expected prefix length that an + // address can be generated for. Must be 64 bits as the interface + // 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 ( + // MinPrefixInformationValidLifetimeForUpdate is the minimum Valid + // Lifetime to update the valid lifetime of a generated address by + // SLAAC. + // + // This is exported as a variable (instead of a constant) so tests + // can update it to a smaller value. + // + // 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 +// NDP Router Advertisement informed the Stack about. +type DHCPv6ConfigurationFromNDPRA int + +const ( + _ DHCPv6ConfigurationFromNDPRA = iota + + // DHCPv6NoConfiguration indicates that no configurations are available via + // DHCPv6. + DHCPv6NoConfiguration + + // DHCPv6ManagedAddress indicates that addresses are available via DHCPv6. + // + // DHCPv6ManagedAddress also implies DHCPv6OtherConfigurations because DHCPv6 + // will return all available configuration information. + DHCPv6ManagedAddress + + // DHCPv6OtherConfigurations indicates that other configuration information is + // available via DHCPv6. + // + // Other configurations are configurations other than addresses. Examples of + // other configurations are recursive DNS server list, DNS search lists and + // default gateway. + DHCPv6OtherConfigurations ) // NDPDispatcher is the interface integrators of netstack must implement to // receive and handle NDP related events. type NDPDispatcher interface { // OnDuplicateAddressDetectionStatus will be called when the DAD process - // for an address (addr) on a NIC (with ID nicid) completes. resolved + // for an address (addr) on a NIC (with ID nicID) completes. resolved // will be set to true if DAD completed successfully (no duplicate addr // detected); false otherwise (addr was detected to be a duplicate on // the link the NIC is a part of, or it was stopped for some other // reason, such as the address being removed). If an error occured // during DAD, err will be set and resolved must be ignored. // - // This function is permitted to block indefinitely without interfering - // with the stack's operation. - OnDuplicateAddressDetectionStatus(nicid tcpip.NICID, addr tcpip.Address, resolved bool, err *tcpip.Error) + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnDuplicateAddressDetectionStatus(nicID tcpip.NICID, addr tcpip.Address, resolved bool, err *tcpip.Error) + + // OnDefaultRouterDiscovered will be called when a new default router is + // discovered. Implementations must return true if the newly discovered + // router should be remembered. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnDefaultRouterDiscovered(nicID tcpip.NICID, addr tcpip.Address) bool + + // OnDefaultRouterInvalidated will be called when a discovered default + // router that was remembered is invalidated. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnDefaultRouterInvalidated(nicID tcpip.NICID, addr tcpip.Address) + + // OnOnLinkPrefixDiscovered will be called when a new on-link prefix is + // discovered. Implementations must return true if the newly discovered + // on-link prefix should be remembered. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnOnLinkPrefixDiscovered(nicID tcpip.NICID, prefix tcpip.Subnet) bool + + // OnOnLinkPrefixInvalidated will be called when a discovered on-link + // prefix that was remembered is invalidated. + // + // This function is not permitted to block indefinitely. This function + // is also not permitted to call into the stack. + OnOnLinkPrefixInvalidated(nicID tcpip.NICID, prefix tcpip.Subnet) + + // OnAutoGenAddress will be called when a new prefix with its + // autonomous address-configuration flag set has been received and SLAAC + // has been performed. Implementations may prevent the stack from + // assigning the address to the NIC by returning false. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnAutoGenAddress(tcpip.NICID, tcpip.AddressWithPrefix) bool + + // OnAutoGenAddressDeprecated will be called when an auto-generated + // address (as part of SLAAC) has been deprecated, but is still + // considered valid. Note, if an address is invalidated at the same + // time it is deprecated, the deprecation event MAY be omitted. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnAutoGenAddressDeprecated(tcpip.NICID, tcpip.AddressWithPrefix) + + // OnAutoGenAddressInvalidated will be called when an auto-generated + // address (as part of SLAAC) has been invalidated. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnAutoGenAddressInvalidated(tcpip.NICID, tcpip.AddressWithPrefix) + + // OnRecursiveDNSServerOption will be called when an NDP option with + // recursive DNS servers has been received. Note, addrs may contain + // link-local addresses. + // + // It is up to the caller to use the DNS Servers only for their valid + // lifetime. OnRecursiveDNSServerOption may be called for new or + // already known DNS servers. If called with known DNS servers, their + // valid lifetimes must be refreshed to lifetime (it may be increased, + // decreased, or completely invalidated when lifetime = 0). + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnRecursiveDNSServerOption(nicID tcpip.NICID, addrs []tcpip.Address, lifetime time.Duration) + + // OnDNSSearchListOption will be called when an NDP option with a DNS + // search list has been received. + // + // It is up to the caller to use the domain names in the search list + // for only their valid lifetime. OnDNSSearchListOption may be called + // with new or already known domain names. If called with known domain + // names, their valid lifetimes must be refreshed to lifetime (it may + // be increased, decreased or completely invalidated when lifetime = 0. + OnDNSSearchListOption(nicID tcpip.NICID, domainNames []string, lifetime time.Duration) + + // OnDHCPv6Configuration will be called with an updated configuration that is + // available via DHCPv6 for a specified NIC. + // + // This function is not permitted to block indefinitely. It must not + // call functions on the stack itself. + OnDHCPv6Configuration(tcpip.NICID, DHCPv6ConfigurationFromNDPRA) } // NDPConfigurations is the NDP configurations for the netstack. @@ -78,28 +317,124 @@ type NDPConfigurations struct { // The amount of time to wait between sending Neighbor solicitation // messages. // - // Must be greater than 0.5s. + // Must be greater than or equal to 1ms. RetransmitTimer time.Duration + + // The number of Router Solicitation messages to send when the NIC + // becomes enabled. + MaxRtrSolicitations uint8 + + // The amount of time between transmitting Router Solicitation messages. + // + // Must be greater than or equal to 0.5s. + RtrSolicitationInterval time.Duration + + // The maximum amount of time before transmitting the first Router + // Solicitation message. + // + // Must be greater than or equal to 0s. + MaxRtrSolicitationDelay time.Duration + + // HandleRAs determines whether or not Router Advertisements will be + // processed. + HandleRAs bool + + // DiscoverDefaultRouters determines whether or not default routers will + // be discovered from Router Advertisements. This configuration is + // ignored if HandleRAs is false. + DiscoverDefaultRouters bool + + // DiscoverOnLinkPrefixes determines whether or not on-link prefixes + // will be discovered from Router Advertisements' Prefix Information + // option. This configuration is ignored if HandleRAs is false. + DiscoverOnLinkPrefixes bool + + // AutoGenGlobalAddresses determines whether or not global IPv6 + // addresses will be generated for a NIC in response to receiving a new + // Prefix Information option with its Autonomous Address + // AutoConfiguration flag set, as a host, as per RFC 4862 (SLAAC). + // + // Note, if an address was already generated for some unique prefix, as + // part of SLAAC, this option does not affect whether or not the + // lifetime(s) of the generated address changes; this option only + // affects the generation of new addresses as part of SLAAC. + AutoGenGlobalAddresses bool + + // AutoGenAddressConflictRetries determines how many times to attempt to retry + // generation of a permanent auto-generated address in response to DAD + // conflicts. + // + // If the method used to generate the address does not support creating + // 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, + 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. func (c *NDPConfigurations) validate() { if c.RetransmitTimer < minimumRetransmitTimer { c.RetransmitTimer = defaultRetransmitTimer } + + if c.RtrSolicitationInterval < minimumRtrSolicitationInterval { + c.RtrSolicitationInterval = defaultRtrSolicitationInterval + } + + 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. @@ -112,13 +447,47 @@ type ndpState struct { // The DAD state to send the next NS message, or resolve the address. dad map[tcpip.Address]dadState + + // The default routers discovered through Router Advertisements. + defaultRouters map[tcpip.Address]defaultRouterState + + rtrSolicit struct { + // The timer used to send the next router solicitation message. + timer tcpip.Timer + + // Used to let the Router Solicitation timer know that it has been stopped. + // + // Must only be read from or written to while protected by the lock of + // the NIC this ndpState is associated with. MUST be set when the timer is + // set. + done *bool + } + + // The on-link prefixes discovered through Router Advertisements' Prefix + // Information option. + onLinkPrefixes map[tcpip.Subnet]onLinkPrefixState + + // The SLAAC prefixes discovered through Router Advertisements' Prefix + // Information option. + slaacPrefixes map[tcpip.Subnet]slaacPrefixState + + // 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 // to the DAD goroutine that DAD should stop. type dadState struct { // The DAD timer to send the next NS message, or resolve the address. - timer *time.Timer + timer tcpip.Timer // Used to let the DAD timer know that it has been stopped. // @@ -127,6 +496,102 @@ type dadState struct { done *bool } +// defaultRouterState holds data associated with a default router discovered by +// a Router Advertisement (RA). +type defaultRouterState struct { + // Job to invalidate the default router. + // + // Must not be nil. + invalidationJob *tcpip.Job +} + +// onLinkPrefixState holds data associated with an on-link prefix discovered by +// a Router Advertisement's Prefix Information option (PI) when the NDP +// configurations was configured to do so. +type onLinkPrefixState struct { + // Job to invalidate the on-link prefix. + // + // Must not be nil. + invalidationJob *tcpip.Job +} + +// tempSLAACAddrState holds state associated with a temporary SLAAC address. +type tempSLAACAddrState struct { + // Job to deprecate the temporary SLAAC address. + // + // Must not be nil. + deprecationJob *tcpip.Job + + // Job to invalidate the temporary SLAAC address. + // + // Must not be nil. + invalidationJob *tcpip.Job + + // Job to regenerate the temporary SLAAC address. + // + // Must not be nil. + regenJob *tcpip.Job + + 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 { + // Job to deprecate the prefix. + // + // Must not be nil. + deprecationJob *tcpip.Job + + // Job to invalidate the prefix. + // + // Must not be nil. + invalidationJob *tcpip.Job + + // Nonzero only when the address is not valid forever. + validUntil time.Time + + // Nonzero only when the address is not preferred forever. + preferredUntil time.Time + + // 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 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 SLAAC address + // in response to DAD conflicts. + maxGenerationAttempts uint8 +} + // startDuplicateAddressDetection performs Duplicate Address Detection. // // This function must only be called by IPv6 addresses that are currently @@ -139,87 +604,110 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref return tcpip.ErrAddressFamilyNotSupported } - // Should not attempt to perform DAD on an address that is currently in - // the DAD process. + if ref.getKind() != permanentTentative { + // The endpoint should be marked as tentative since we are starting DAD. + panic(fmt.Sprintf("ndpdad: addr %s is not tentative on NIC(%d)", addr, ndp.nic.ID())) + } + + // Should not attempt to perform DAD on an address that is currently in the + // DAD process. if _, ok := ndp.dad[addr]; ok { - // Should never happen because we should only ever call this - // function for newly created addresses. If we attemped to - // "add" an address that already existed, we would returned an - // error since we attempted to add a duplicate address, or its - // reference count would have been increased without doing the - // work that would have been done for an address that was brand - // new. See NIC.addPermanentAddressLocked. + // Should never happen because we should only ever call this function for + // newly created addresses. If we attemped to "add" an address that already + // existed, we would get an error since we attempted to add a duplicate + // address, or its reference count would have been increased without doing + // the work that would have been done for an address that was brand new. + // See NIC.addAddressLocked. panic(fmt.Sprintf("ndpdad: already performing DAD for addr %s on NIC(%d)", addr, ndp.nic.ID())) } remaining := ndp.configs.DupAddrDetectTransmits + if remaining == 0 { + ref.setKind(permanent) - { - done, err := ndp.doDuplicateAddressDetection(addr, remaining, ref) - if err != nil { - return err - } - if done { - return nil + // Consider DAD to have resolved even if no DAD messages were actually + // transmitted. + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, true, nil) } - } - remaining-- + return nil + } var done bool - var timer *time.Timer - timer = time.AfterFunc(ndp.configs.RetransmitTimer, func() { - var d bool - var err *tcpip.Error + var timer tcpip.Timer + // We initially start a timer to fire immediately because some of the DAD work + // cannot be done while holding the NIC's lock. This is effectively the same + // as starting a goroutine but we use a timer that fires immediately so we can + // reset it for the next DAD iteration. + timer = ndp.nic.stack.Clock().AfterFunc(0, func() { + ndp.nic.mu.Lock() + defer ndp.nic.mu.Unlock() - // doDadIteration does a single iteration of the DAD loop. - // - // Returns true if the integrator needs to be informed of DAD - // completing. - doDadIteration := func() bool { - ndp.nic.mu.Lock() - defer ndp.nic.mu.Unlock() - - if done { - // If we reach this point, it means that the DAD - // timer fired after another goroutine already - // obtained the NIC lock and stopped DAD before - // this function obtained the NIC lock. Simply - // return here and do nothing further. - return false - } + if done { + // If we reach this point, it means that the DAD timer fired after + // another goroutine already obtained the NIC lock and stopped DAD + // before this function obtained the NIC lock. Simply return here and do + // nothing further. + return + } - ref, ok := ndp.nic.endpoints[NetworkEndpointID{addr}] - if !ok { - // This should never happen. - // We should have an endpoint for addr since we - // are still performing DAD on it. If the - // endpoint does not exist, but we are doing DAD - // on it, then we started DAD at some point, but - // forgot to stop it when the endpoint was - // deleted. - panic(fmt.Sprintf("ndpdad: unrecognized addr %s for NIC(%d)", addr, ndp.nic.ID())) - } + if ref.getKind() != permanentTentative { + // The endpoint should still be marked as tentative since we are still + // performing DAD on it. + panic(fmt.Sprintf("ndpdad: addr %s is no longer tentative on NIC(%d)", addr, ndp.nic.ID())) + } - d, err = ndp.doDuplicateAddressDetection(addr, remaining, ref) - if err != nil || d { - delete(ndp.dad, addr) + dadDone := remaining == 0 - if err != nil { - log.Printf("ndpdad: Error occured during DAD iteration for addr (%s) on NIC(%d); err = %s", addr, ndp.nic.ID(), err) - } + var err *tcpip.Error + if !dadDone { + // Use the unspecified address as the source address when performing DAD. + ref := ndp.nic.getRefOrCreateTempLocked(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint) - // Let the integrator know DAD has completed. - return true - } + // Do not hold the lock when sending packets which may be a long running + // task or may block link address resolution. We know this is safe + // because immediately after obtaining the lock again, we check if DAD + // has been stopped before doing any work with the NIC. Note, DAD would be + // stopped if the NIC was disabled or removed, or if the address was + // removed. + ndp.nic.mu.Unlock() + err = ndp.sendDADPacket(addr, ref) + ndp.nic.mu.Lock() + } + 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. + return + } + + if dadDone { + // DAD has resolved. + ref.setKind(permanent) + } else if err == nil { + // DAD is not done and we had no errors when sending the last NDP NS, + // schedule the next DAD timer. remaining-- timer.Reset(ndp.nic.stack.ndpConfigs.RetransmitTimer) - return false + return + } + + // At this point we know that either DAD is done or we hit an error sending + // the last NDP NS. Either way, clean up addr's DAD state and let the + // integrator know DAD has completed. + delete(ndp.dad, addr) + + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, dadDone, err) } - if doDadIteration() && ndp.nic.stack.ndpDisp != nil { - ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, d, 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 */) } }) @@ -231,60 +719,58 @@ func (ndp *ndpState) startDuplicateAddressDetection(addr tcpip.Address, ref *ref return nil } -// doDuplicateAddressDetection is called on every iteration of the timer, and -// when DAD starts. -// -// It handles resolving the address (if there are no more NS to send), or -// sending the next NS if there are more NS to send. -// -// This function must only be called by IPv6 addresses that are currently -// tentative. +// sendDADPacket sends a NS message to see if any nodes on ndp's NIC's link owns +// addr. // -// The NIC that ndp belongs to (n) MUST be locked. +// addr must be a tentative IPv6 address on ndp's NIC. // -// Returns true if DAD has resolved; false if DAD is still ongoing. -func (ndp *ndpState) doDuplicateAddressDetection(addr tcpip.Address, remaining uint8, ref *referencedNetworkEndpoint) (bool, *tcpip.Error) { - if ref.getKind() != permanentTentative { - // The endpoint should still be marked as tentative - // since we are still performing DAD on it. - panic(fmt.Sprintf("ndpdad: addr %s is not tentative on NIC(%d)", addr, ndp.nic.ID())) - } +// The NIC ndp belongs to MUST NOT be locked. +func (ndp *ndpState) sendDADPacket(addr tcpip.Address, ref *referencedNetworkEndpoint) *tcpip.Error { + snmc := header.SolicitedNodeAddr(addr) - if remaining == 0 { - // DAD has resolved. - ref.setKind(permanent) - return true, nil - } + r := makeRoute(header.IPv6ProtocolNumber, ref.address(), snmc, ndp.nic.linkEP.LinkAddress(), ref, false, false) + defer r.Release() - // Send a new NS. - snmc := header.SolicitedNodeAddr(addr) - snmcRef, ok := ndp.nic.endpoints[NetworkEndpointID{snmc}] - if !ok { - // This should never happen as if we have the - // address, we should have the solicited-node - // address. - panic(fmt.Sprintf("ndpdad: NIC(%d) is not in the solicited-node multicast group (%s) but it has addr %s", ndp.nic.ID(), snmc, addr)) - } + // Route should resolve immediately since snmc is a multicast address so a + // remote link address can be calculated without a resolution process. + if c, err := r.Resolve(nil); err != nil { + // Do not consider the NIC being unknown or disabled as a fatal error. + // Since this method is required to be called when the NIC is not locked, + // the NIC could have been disabled or removed by another goroutine. + if err == tcpip.ErrUnknownNICID || err != tcpip.ErrInvalidEndpointState { + return err + } - // Use the unspecified address as the source address when performing - // DAD. - r := makeRoute(header.IPv6ProtocolNumber, header.IPv6Any, snmc, ndp.nic.linkEP.LinkAddress(), snmcRef, false, false) + panic(fmt.Sprintf("ndp: error when resolving route to send NDP NS for DAD (%s -> %s on NIC(%d)): %s", header.IPv6Any, snmc, ndp.nic.ID(), err)) + } else if c != nil { + panic(fmt.Sprintf("ndp: route resolution not immediate for route to send NDP NS for DAD (%s -> %s on NIC(%d))", header.IPv6Any, snmc, ndp.nic.ID())) + } - hdr := buffer.NewPrependable(int(r.MaxHeaderLength()) + header.ICMPv6NeighborSolicitMinimumSize) - pkt := header.ICMPv6(hdr.Prepend(header.ICMPv6NeighborSolicitMinimumSize)) - pkt.SetType(header.ICMPv6NeighborSolicit) - ns := header.NDPNeighborSolicit(pkt.NDPPayload()) + icmpData := header.ICMPv6(buffer.NewView(header.ICMPv6NeighborSolicitMinimumSize)) + icmpData.SetType(header.ICMPv6NeighborSolicit) + ns := header.NDPNeighborSolicit(icmpData.NDPPayload()) ns.SetTargetAddress(addr) - pkt.SetChecksum(header.ICMPv6Checksum(pkt, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) + icmpData.SetChecksum(header.ICMPv6Checksum(icmpData, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) + + pkt := NewPacketBuffer(PacketBufferOptions{ + ReserveHeaderBytes: int(r.MaxHeaderLength()), + Data: buffer.View(icmpData).ToVectorisedView(), + }) sent := r.Stats().ICMP.V6PacketsSent - if err := r.WritePacket(nil, hdr, buffer.VectorisedView{}, NetworkHeaderParams{Protocol: header.ICMPv6ProtocolNumber, TTL: header.NDPHopLimit, TOS: DefaultTOS}); err != nil { + if err := r.WritePacket(nil, + NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: header.NDPHopLimit, + TOS: DefaultTOS, + }, pkt, + ); err != nil { sent.Dropped.Increment() - return false, err + return err } sent.NeighborSolicit.Increment() - return false, nil + return nil } // stopDuplicateAddressDetection ends a running Duplicate Address Detection @@ -315,7 +801,1173 @@ func (ndp *ndpState) stopDuplicateAddressDetection(addr tcpip.Address) { delete(ndp.dad, addr) // Let the integrator know DAD did not resolve. - if ndp.nic.stack.ndpDisp != nil { - go ndp.nic.stack.ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, false, nil) + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnDuplicateAddressDetectionStatus(ndp.nic.ID(), addr, false, nil) + } +} + +// handleRA handles a Router Advertisement message that arrived on the NIC +// this ndp is for. Does nothing if the NIC is configured to not handle RAs. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) handleRA(ip tcpip.Address, ra header.NDPRouterAdvert) { + // Is the NIC configured to handle RAs at all? + // + // Currently, the stack does not determine router interface status on a + // per-interface basis; it is a stack-wide configuration, so we check + // stack's forwarding flag to determine if the NIC is a routing + // interface. + if !ndp.configs.HandleRAs || ndp.nic.stack.Forwarding(header.IPv6ProtocolNumber) { + return + } + + // Only worry about the DHCPv6 configuration if we have an NDPDispatcher as we + // only inform the dispatcher on configuration changes. We do nothing else + // with the information. + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + var configuration DHCPv6ConfigurationFromNDPRA + switch { + case ra.ManagedAddrConfFlag(): + configuration = DHCPv6ManagedAddress + + case ra.OtherConfFlag(): + configuration = DHCPv6OtherConfigurations + + default: + configuration = DHCPv6NoConfiguration + } + + if ndp.dhcpv6Configuration != configuration { + ndp.dhcpv6Configuration = configuration + ndpDisp.OnDHCPv6Configuration(ndp.nic.ID(), configuration) + } + } + + // Is the NIC configured to discover default routers? + if ndp.configs.DiscoverDefaultRouters { + rtr, ok := ndp.defaultRouters[ip] + rl := ra.RouterLifetime() + switch { + case !ok && rl != 0: + // This is a new default router we are discovering. + // + // Only remember it if we currently know about less than + // MaxDiscoveredDefaultRouters routers. + if len(ndp.defaultRouters) < MaxDiscoveredDefaultRouters { + ndp.rememberDefaultRouter(ip, rl) + } + + case ok && rl != 0: + // This is an already discovered default router. Update + // the invalidation job. + rtr.invalidationJob.Cancel() + rtr.invalidationJob.Schedule(rl) + ndp.defaultRouters[ip] = rtr + + case ok && rl == 0: + // We know about the router but it is no longer to be + // used as a default router so invalidate it. + ndp.invalidateDefaultRouter(ip) + } + } + + // TODO(b/141556115): Do (RetransTimer, ReachableTime)) Parameter + // Discovery. + + // We know the options is valid as far as wire format is concerned since + // we got the Router Advertisement, as documented by this fn. Given this + // we do not check the iterator for errors on calls to Next. + it, _ := ra.Options().Iter(false) + for opt, done, _ := it.Next(); !done; opt, done, _ = it.Next() { + switch opt := opt.(type) { + case header.NDPRecursiveDNSServer: + if ndp.nic.stack.ndpDisp == nil { + continue + } + + addrs, _ := opt.Addresses() + ndp.nic.stack.ndpDisp.OnRecursiveDNSServerOption(ndp.nic.ID(), addrs, opt.Lifetime()) + + case header.NDPDNSSearchList: + if ndp.nic.stack.ndpDisp == nil { + continue + } + + domainNames, _ := opt.DomainNames() + ndp.nic.stack.ndpDisp.OnDNSSearchListOption(ndp.nic.ID(), domainNames, opt.Lifetime()) + + case header.NDPPrefixInformation: + prefix := opt.Subnet() + + // Is the prefix a link-local? + if header.IsV6LinkLocalAddress(prefix.ID()) { + // ...Yes, skip as per RFC 4861 section 6.3.4, + // and RFC 4862 section 5.5.3.b (for SLAAC). + continue + } + + // Is the Prefix Length 0? + if prefix.Prefix() == 0 { + // ...Yes, skip as this is an invalid prefix + // as all IPv6 addresses cannot be on-link. + continue + } + + if opt.OnLinkFlag() { + ndp.handleOnLinkPrefixInformation(opt) + } + + if opt.AutonomousAddressConfigurationFlag() { + ndp.handleAutonomousPrefixInformation(opt) + } + } + + // TODO(b/141556115): Do (MTU) Parameter Discovery. + } +} + +// invalidateDefaultRouter invalidates a discovered default router. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) invalidateDefaultRouter(ip tcpip.Address) { + rtr, ok := ndp.defaultRouters[ip] + + // Is the router still discovered? + if !ok { + // ...Nope, do nothing further. + return + } + + rtr.invalidationJob.Cancel() + delete(ndp.defaultRouters, ip) + + // Let the integrator know a discovered default router is invalidated. + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnDefaultRouterInvalidated(ndp.nic.ID(), ip) + } +} + +// rememberDefaultRouter remembers a newly discovered default router with IPv6 +// link-local address ip with lifetime rl. +// +// The router identified by ip MUST NOT already be known by the NIC. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) rememberDefaultRouter(ip tcpip.Address, rl time.Duration) { + ndpDisp := ndp.nic.stack.ndpDisp + if ndpDisp == nil { + return + } + + // Inform the integrator when we discovered a default router. + if !ndpDisp.OnDefaultRouterDiscovered(ndp.nic.ID(), ip) { + // Informed by the integrator to not remember the router, do + // nothing further. + return + } + + state := defaultRouterState{ + invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() { + ndp.invalidateDefaultRouter(ip) + }), + } + + state.invalidationJob.Schedule(rl) + + ndp.defaultRouters[ip] = state +} + +// rememberOnLinkPrefix remembers a newly discovered on-link prefix with IPv6 +// address with prefix prefix with lifetime l. +// +// The prefix identified by prefix MUST NOT already be known. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) rememberOnLinkPrefix(prefix tcpip.Subnet, l time.Duration) { + ndpDisp := ndp.nic.stack.ndpDisp + if ndpDisp == nil { + return + } + + // Inform the integrator when we discovered an on-link prefix. + if !ndpDisp.OnOnLinkPrefixDiscovered(ndp.nic.ID(), prefix) { + // Informed by the integrator to not remember the prefix, do + // nothing further. + return + } + + state := onLinkPrefixState{ + invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() { + ndp.invalidateOnLinkPrefix(prefix) + }), + } + + if l < header.NDPInfiniteLifetime { + state.invalidationJob.Schedule(l) + } + + ndp.onLinkPrefixes[prefix] = state +} + +// invalidateOnLinkPrefix invalidates a discovered on-link prefix. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) invalidateOnLinkPrefix(prefix tcpip.Subnet) { + s, ok := ndp.onLinkPrefixes[prefix] + + // Is the on-link prefix still discovered? + if !ok { + // ...Nope, do nothing further. + return + } + + s.invalidationJob.Cancel() + delete(ndp.onLinkPrefixes, prefix) + + // Let the integrator know a discovered on-link prefix is invalidated. + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnOnLinkPrefixInvalidated(ndp.nic.ID(), prefix) + } +} + +// handleOnLinkPrefixInformation handles a Prefix Information option with +// its on-link flag set, as per RFC 4861 section 6.3.4. +// +// handleOnLinkPrefixInformation assumes that the prefix this pi is for is +// not the link-local prefix and the on-link flag is set. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) handleOnLinkPrefixInformation(pi header.NDPPrefixInformation) { + prefix := pi.Subnet() + prefixState, ok := ndp.onLinkPrefixes[prefix] + vl := pi.ValidLifetime() + + if !ok && vl == 0 { + // Don't know about this prefix but it has a zero valid + // lifetime, so just ignore. + return + } + + if !ok && vl != 0 { + // This is a new on-link prefix we are discovering + // + // Only remember it if we currently know about less than + // MaxDiscoveredOnLinkPrefixes on-link prefixes. + if ndp.configs.DiscoverOnLinkPrefixes && len(ndp.onLinkPrefixes) < MaxDiscoveredOnLinkPrefixes { + ndp.rememberOnLinkPrefix(prefix, vl) + } + return + } + + if ok && vl == 0 { + // We know about the on-link prefix, but it is + // no longer to be considered on-link, so + // invalidate it. + ndp.invalidateOnLinkPrefix(prefix) + return + } + + // This is an already discovered on-link prefix with a + // new non-zero valid lifetime. + // + // Update the invalidation job. + + prefixState.invalidationJob.Cancel() + + if vl < header.NDPInfiniteLifetime { + // Prefix is valid for a finite lifetime, schedule the job to execute after + // the new valid lifetime. + prefixState.invalidationJob.Schedule(vl) + } + + ndp.onLinkPrefixes[prefix] = prefixState +} + +// handleAutonomousPrefixInformation handles a Prefix Information option with +// its autonomous flag set, as per RFC 4862 section 5.5.3. +// +// handleAutonomousPrefixInformation assumes that the prefix this pi is for is +// not the link-local prefix and the autonomous flag is set. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) handleAutonomousPrefixInformation(pi header.NDPPrefixInformation) { + vl := pi.ValidLifetime() + pl := pi.PreferredLifetime() + + // If the preferred lifetime is greater than the valid lifetime, + // silently ignore the Prefix Information option, as per RFC 4862 + // section 5.5.3.c. + if pl > vl { + return + } + + prefix := pi.Subnet() + + // Check if we already maintain SLAAC state for prefix. + if state, ok := ndp.slaacPrefixes[prefix]; ok { + // As per RFC 4862 section 5.5.3.e, refresh prefix's SLAAC lifetimes. + ndp.refreshSLAACPrefixLifetimes(prefix, &state, pl, vl) + ndp.slaacPrefixes[prefix] = state + return + } + + // prefix is a new SLAAC prefix. Do the work as outlined by RFC 4862 section + // 5.5.3.d if ndp is configured to auto-generate new addresses via SLAAC. + if !ndp.configs.AutoGenGlobalAddresses { + return + } + + ndp.doSLAAC(prefix, pl, vl) +} + +// doSLAAC generates a new SLAAC address with the provided lifetimes +// for 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) doSLAAC(prefix tcpip.Subnet, pl, vl time.Duration) { + // If we do not already have an address for this prefix and the valid + // lifetime is 0, no need to do anything further, as per RFC 4862 + // section 5.5.3.d. + if vl == 0 { + return + } + + // Make sure the prefix is valid (as far as its length is concerned) to + // generate a valid IPv6 address from an interface identifier (IID), as + // per RFC 4862 sectiion 5.5.3.d. + if prefix.Prefix() != validPrefixLenForAutoGen { + return + } + + state := slaacPrefixState{ + deprecationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() { + state, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for the deprecated SLAAC prefix %s", prefix)) + } + + ndp.deprecateSLAACAddress(state.stableAddr.ref) + }), + invalidationJob: ndp.nic.stack.newJob(&ndp.nic.mu, func() { + state, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: must have a slaacPrefixes entry for the invalidated SLAAC prefix %s", prefix)) + } + + ndp.invalidateSLAACPrefix(prefix, state) + }), + tempAddrs: make(map[tcpip.Address]tempSLAACAddrState), + maxGenerationAttempts: ndp.configs.AutoGenAddressConflictRetries + 1, + } + + now := time.Now() + + // The time an address is preferred until is needed to properly generate the + // address. + if pl < header.NDPInfiniteLifetime { + state.preferredUntil = now.Add(pl) + } + + if !ndp.generateSLAACAddr(prefix, &state) { + // We were unable to generate an address for the prefix, we do not nothing + // further as there is no reason to maintain state or jobs for a prefix we + // do not have an address for. + return + } + + // Setup the initial jobs to deprecate and invalidate prefix. + + if pl < header.NDPInfiniteLifetime && pl != 0 { + state.deprecationJob.Schedule(pl) + } + + if vl < header.NDPInfiniteLifetime { + state.invalidationJob.Schedule(vl) + 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. +// +// Panics if the prefix is not a SLAAC prefix or it already has an address. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) generateSLAACAddr(prefix tcpip.Subnet, state *slaacPrefixState) bool { + if r := state.stableAddr.ref; r != nil { + panic(fmt.Sprintf("ndp: SLAAC prefix %s already has a permenant address %s", prefix, r.addrWithPrefix())) + } + + // If we have already reached the maximum address generation attempts for the + // prefix, do not generate another address. + if state.generationAttempts == state.maxGenerationAttempts { + return false + } + + var generatedAddr tcpip.AddressWithPrefix + addrBytes := []byte(prefix.ID()) + + 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 + } + + 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 + } + + // 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 !ndp.nic.hasPermanentAddrLocked(generatedAddr.Address) { + break + } + + state.stableAddr.localGenerationFailures++ + } + + if ref := ndp.addSLAACAddr(generatedAddr, slaac, time.Since(state.preferredUntil) >= 0 /* deprecated */); ref != nil { + state.stableAddr.ref = ref + state.generationAttempts++ + return true + } + + return false +} + +// regenerateSLAACAddr regenerates an address for a SLAAC prefix. +// +// If generating a new address for the prefix fails, the prefix will be +// invalidated. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) regenerateSLAACAddr(prefix tcpip.Subnet) { + state, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: SLAAC prefix state not found to regenerate address for %s", prefix)) + } + + if ndp.generateSLAACAddr(prefix, &state) { + ndp.slaacPrefixes[prefix] = state + return + } + + // We were unable to generate a permanent address for the SLAAC prefix so + // invalidate the prefix as there is no reason to maintain state for a + // SLAAC prefix we do not have an address for. + ndp.invalidateSLAACPrefix(prefix, state) +} + +// generateTempSLAACAddr generates a new temporary SLAAC address. +// +// 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.address() + 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{ + deprecationJob: ndp.nic.stack.newJob(&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) + }), + invalidationJob: ndp.nic.stack.newJob(&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) + }), + regenJob: ndp.nic.stack.newJob(&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.deprecationJob.Schedule(pl) + state.invalidationJob.Schedule(vl) + state.regenJob.Schedule(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) regenerateTempSLAACAddr(prefix tcpip.Subnet, resetGenAttempts bool) { + state, ok := ndp.slaacPrefixes[prefix] + if !ok { + panic(fmt.Sprintf("ndp: SLAAC prefix state not found to regenerate temporary address for %s", prefix)) + } + + 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.stableAddr.ref) + } else { + prefixState.stableAddr.ref.deprecated = false + } + + // If prefix was preferred for some finite lifetime before, cancel the + // deprecation job so it can be reset. + prefixState.deprecationJob.Cancel() + + now := time.Now() + + // Schedule the deprecation job if prefix has a finite preferred lifetime. + if pl < header.NDPInfiniteLifetime { + if !deprecated { + prefixState.deprecationJob.Schedule(pl) + } + prefixState.preferredUntil = now.Add(pl) + } else { + prefixState.preferredUntil = time.Time{} + } + + // As per RFC 4862 section 5.5.3.e, update the valid lifetime for prefix: + // + // 1) If the received Valid Lifetime is greater than 2 hours or greater than + // RemainingLifetime, set the valid lifetime of the prefix to the + // advertised Valid Lifetime. + // + // 2) If RemainingLifetime is less than or equal to 2 hours, ignore the + // advertised Valid Lifetime. + // + // 3) Otherwise, reset the valid lifetime of the prefix to 2 hours. + + if vl >= header.NDPInfiniteLifetime { + // Handle the infinite valid lifetime separately as we do not schedule a + // job in this case. + prefixState.invalidationJob.Cancel() + prefixState.validUntil = time.Time{} + } else { + 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 vl > MinPrefixInformationValidLifetimeForUpdate || vl > rl { + effectiveVl = vl + } else if rl > MinPrefixInformationValidLifetimeForUpdate { + effectiveVl = MinPrefixInformationValidLifetimeForUpdate + } + + if effectiveVl != 0 { + prefixState.invalidationJob.Cancel() + prefixState.invalidationJob.Schedule(effectiveVl) + prefixState.validUntil = now.Add(effectiveVl) + } + } + + // 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 + } + + // Note, we do not need to update the entries in the temporary address map + // after updating the jobs because the jobs 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 job. + newValidLifetime := validUntil.Sub(now) + if newValidLifetime <= 0 { + ndp.invalidateTempSLAACAddr(prefixState.tempAddrs, tempAddr, tempAddrState) + continue + } + tempAddrState.invalidationJob.Cancel() + tempAddrState.invalidationJob.Schedule(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, schedule the deprecation job again. + newPreferredLifetime := preferredUntil.Sub(now) + tempAddrState.deprecationJob.Cancel() + if newPreferredLifetime <= 0 { + ndp.deprecateSLAACAddress(tempAddrState.ref) + } else { + tempAddrState.ref.deprecated = false + tempAddrState.deprecationJob.Schedule(newPreferredLifetime) + } + + tempAddrState.regenJob.Cancel() + 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.regenJob.Schedule(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 +// dispatcher that ref has been deprecated. +// +// deprecateSLAACAddress does nothing if ref is already deprecated. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) deprecateSLAACAddress(ref *referencedNetworkEndpoint) { + if ref.deprecated { + return + } + + ref.deprecated = true + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnAutoGenAddressDeprecated(ndp.nic.ID(), ref.addrWithPrefix()) + } +} + +// invalidateSLAACPrefix invalidates a SLAAC prefix. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) invalidateSLAACPrefix(prefix tcpip.Subnet, state slaacPrefixState) { + 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 /* allowSLAACInvalidation */); err != nil { + panic(fmt.Sprintf("ndp: error removing stable SLAAC address %s: %s", r.addrWithPrefix(), err)) + } + } + + ndp.cleanupSLAACPrefixResources(prefix, state) +} + +// cleanupSLAACAddrResourcesAndNotify cleans up an invalidated SLAAC address's +// resources. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) cleanupSLAACAddrResourcesAndNotify(addr tcpip.AddressWithPrefix, invalidatePrefix bool) { + if ndpDisp := ndp.nic.stack.ndpDisp; ndpDisp != nil { + ndpDisp.OnAutoGenAddressInvalidated(ndp.nic.ID(), addr) + } + + prefix := addr.Subnet() + state, ok := ndp.slaacPrefixes[prefix] + if !ok || state.stableAddr.ref == nil || addr.Address != state.stableAddr.ref.address() { + return + } + + if !invalidatePrefix { + // If the prefix is not being invalidated, disassociate the address from the + // prefix and do nothing further. + state.stableAddr.ref = nil + ndp.slaacPrefixes[prefix] = state + return + } + + ndp.cleanupSLAACPrefixResources(prefix, state) +} + +// cleanupSLAACPrefixResources cleans up a SLAAC prefix's jobs and entry. +// +// Panics if the SLAAC prefix is not known. +// +// 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.deprecationJob.Cancel() + state.invalidationJob.Cancel() + 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 +// jobs 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.deprecationJob.Cancel() + tempAddrState.invalidationJob.Cancel() + tempAddrState.regenJob.Cancel() + delete(tempAddrs, tempAddr) +} + +// cleanupState cleans up ndp's state. +// +// If hostOnly is true, then only host-specific state will be cleaned up. +// +// cleanupState MUST be called with hostOnly set to true when ndp's NIC is +// transitioning from a host to a router. This function will invalidate all +// discovered on-link prefixes, discovered routers, and auto-generated +// addresses. +// +// If hostOnly is true, then the link-local auto-generated address will not be +// invalidated as routers are also expected to generate a link-local address. +// +// The NIC that ndp belongs to MUST be locked. +func (ndp *ndpState) cleanupState(hostOnly bool) { + linkLocalSubnet := header.IPv6LinkLocalPrefix.Subnet() + linkLocalPrefixes := 0 + for prefix, state := range ndp.slaacPrefixes { + // RFC 4862 section 5 states that routers are also expected to generate a + // link-local address so we do not invalidate them if we are cleaning up + // host-only state. + if hostOnly && prefix == linkLocalSubnet { + linkLocalPrefixes++ + continue + } + + ndp.invalidateSLAACPrefix(prefix, state) + } + + if got := len(ndp.slaacPrefixes); got != linkLocalPrefixes { + panic(fmt.Sprintf("ndp: still have non-linklocal SLAAC prefixes after cleaning up; found = %d prefixes, of which %d are link-local", got, linkLocalPrefixes)) + } + + for prefix := range ndp.onLinkPrefixes { + ndp.invalidateOnLinkPrefix(prefix) + } + + if got := len(ndp.onLinkPrefixes); got != 0 { + panic(fmt.Sprintf("ndp: still have discovered on-link prefixes after cleaning up; found = %d", got)) + } + + for router := range ndp.defaultRouters { + ndp.invalidateDefaultRouter(router) + } + + 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 +// 6.3.7. If routers are already being solicited, this function does nothing. +// +// The NIC ndp belongs to MUST be locked. +func (ndp *ndpState) startSolicitingRouters() { + if ndp.rtrSolicit.timer != nil { + // We are already soliciting routers. + return + } + + remaining := ndp.configs.MaxRtrSolicitations + if remaining == 0 { + return + } + + // Calculate the random delay before sending our first RS, as per RFC + // 4861 section 6.3.7. + var delay time.Duration + if ndp.configs.MaxRtrSolicitationDelay > 0 { + delay = time.Duration(rand.Int63n(int64(ndp.configs.MaxRtrSolicitationDelay))) + } + + var done bool + ndp.rtrSolicit.done = &done + ndp.rtrSolicit.timer = ndp.nic.stack.Clock().AfterFunc(delay, func() { + ndp.nic.mu.Lock() + if done { + // If we reach this point, it means that the RS timer fired after another + // goroutine already obtained the NIC lock and stopped solicitations. + // Simply return here and do nothing further. + ndp.nic.mu.Unlock() + return + } + + // As per RFC 4861 section 4.1, the source of the RS is an address assigned + // to the sending interface, or the unspecified address if no address is + // assigned to the sending interface. + ref := ndp.nic.primaryIPv6EndpointRLocked(header.IPv6AllRoutersMulticastAddress) + if ref == nil { + ref = ndp.nic.getRefOrCreateTempLocked(header.IPv6ProtocolNumber, header.IPv6Any, NeverPrimaryEndpoint) + } + ndp.nic.mu.Unlock() + + localAddr := ref.address() + r := makeRoute(header.IPv6ProtocolNumber, localAddr, header.IPv6AllRoutersMulticastAddress, ndp.nic.linkEP.LinkAddress(), ref, false, false) + defer r.Release() + + // Route should resolve immediately since + // header.IPv6AllRoutersMulticastAddress is a multicast address so a + // remote link address can be calculated without a resolution process. + if c, err := r.Resolve(nil); err != nil { + // Do not consider the NIC being unknown or disabled as a fatal error. + // Since this method is required to be called when the NIC is not locked, + // the NIC could have been disabled or removed by another goroutine. + if err == tcpip.ErrUnknownNICID || err == tcpip.ErrInvalidEndpointState { + return + } + + panic(fmt.Sprintf("ndp: error when resolving route to send NDP RS (%s -> %s on NIC(%d)): %s", header.IPv6Any, header.IPv6AllRoutersMulticastAddress, ndp.nic.ID(), err)) + } else if c != nil { + panic(fmt.Sprintf("ndp: route resolution not immediate for route to send NDP RS (%s -> %s on NIC(%d))", header.IPv6Any, header.IPv6AllRoutersMulticastAddress, ndp.nic.ID())) + } + + // As per RFC 4861 section 4.1, an NDP RS SHOULD include the source + // link-layer address option if the source address of the NDP RS is + // specified. This option MUST NOT be included if the source address is + // unspecified. + // + // TODO(b/141011931): Validate a LinkEndpoint's link address (provided by + // LinkEndpoint.LinkAddress) before reaching this point. + var optsSerializer header.NDPOptionsSerializer + if localAddr != header.IPv6Any && header.IsValidUnicastEthernetAddress(r.LocalLinkAddress) { + optsSerializer = header.NDPOptionsSerializer{ + header.NDPSourceLinkLayerAddressOption(r.LocalLinkAddress), + } + } + payloadSize := header.ICMPv6HeaderSize + header.NDPRSMinimumSize + int(optsSerializer.Length()) + icmpData := header.ICMPv6(buffer.NewView(payloadSize)) + icmpData.SetType(header.ICMPv6RouterSolicit) + rs := header.NDPRouterSolicit(icmpData.NDPPayload()) + rs.Options().Serialize(optsSerializer) + icmpData.SetChecksum(header.ICMPv6Checksum(icmpData, r.LocalAddress, r.RemoteAddress, buffer.VectorisedView{})) + + pkt := NewPacketBuffer(PacketBufferOptions{ + ReserveHeaderBytes: int(r.MaxHeaderLength()), + Data: buffer.View(icmpData).ToVectorisedView(), + }) + + sent := r.Stats().ICMP.V6PacketsSent + if err := r.WritePacket(nil, + NetworkHeaderParams{ + Protocol: header.ICMPv6ProtocolNumber, + TTL: header.NDPHopLimit, + TOS: DefaultTOS, + }, pkt, + ); err != nil { + sent.Dropped.Increment() + log.Printf("startSolicitingRouters: error writing NDP router solicit message on NIC(%d); err = %s", ndp.nic.ID(), err) + // Don't send any more messages if we had an error. + remaining = 0 + } else { + sent.RouterSolicit.Increment() + remaining-- + } + + ndp.nic.mu.Lock() + if done || remaining == 0 { + ndp.rtrSolicit.timer = nil + ndp.rtrSolicit.done = nil + } else if ndp.rtrSolicit.timer != nil { + // Note, we need to explicitly check to make sure that + // the timer field is not nil because if it was nil but + // we still reached this point, then we know the NIC + // was requested to stop soliciting routers so we don't + // need to send the next Router Solicitation message. + ndp.rtrSolicit.timer.Reset(ndp.configs.RtrSolicitationInterval) + } + ndp.nic.mu.Unlock() + }) + +} + +// stopSolicitingRouters stops soliciting routers. If routers are not currently +// being solicited, this function does nothing. +// +// The NIC ndp belongs to MUST be locked. +func (ndp *ndpState) stopSolicitingRouters() { + if ndp.rtrSolicit.timer == nil { + // Nothing to do. + return + } + + *ndp.rtrSolicit.done = true + ndp.rtrSolicit.timer.Stop() + ndp.rtrSolicit.timer = nil + ndp.rtrSolicit.done = 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))) } } |