ipv6

package
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 Go to latest Published: May 9, 2021 License: Apache-2.0, MIT Imports: 20 Imported by: 0

Documentation

Overview

Package ipv6 contains the implementation of the ipv6 network protocol.

Index

Constants

View Source 
const (
	// ReassembleTimeout controls how long a fragment will be held.
	// As per RFC 8200 section 4.5:
	//
	//   If insufficient fragments are received to complete reassembly of a packet
	//   within 60 seconds of the reception of the first-arriving fragment of that
	//   packet, reassembly of that packet must be abandoned.
	//
	// Linux also uses 60 seconds for reassembly timeout:
	// https://github.com/torvalds/linux/blob/47ec5303d73ea344e84f46660fff693c57641386/include/net/ipv6.h#L456
	ReassembleTimeout = 60 * time.Second

	// ProtocolNumber is the ipv6 protocol number.
	ProtocolNumber = header.IPv6ProtocolNumber

	// DefaultTTL is the default hop limit for IPv6 Packets egressed by
	// Netstack.
	DefaultTTL = 64
)
View Source 
const (

	// 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
)
View Source 
const (
	// UnsolicitedReportIntervalMax is the maximum delay between sending
	// unsolicited MLD reports.
	//
	// Obtained from RFC 2710 Section 7.10.
	UnsolicitedReportIntervalMax = 10 * time.Second
)

Variables

View Source 
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 is 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 is valid for at least
	// 2hrs if the SLAAC prefix is valid for at least that time.
	MinMaxTempAddrValidLifetime = 2 * time.Hour
)

Functions

func NewProtocol 

func NewProtocol(s *stack.Stack) stack.NetworkProtocol

NewProtocol is equivalent to NewProtocolWithOptions with an empty Options.

func NewProtocolWithOptions 

func NewProtocolWithOptions(opts Options) stack.NetworkProtocolFactory

NewProtocolWithOptions returns an IPv6 network protocol.

Types

type DHCPv6ConfigurationFromNDPRA 

type DHCPv6ConfigurationFromNDPRA int

DHCPv6ConfigurationFromNDPRA is a configuration available via DHCPv6 that an NDP Router Advertisement informed the Stack about. 

const (

	// DHCPv6NoConfiguration indicates that no configurations are available via
	// DHCPv6.
	DHCPv6NoConfiguration DHCPv6ConfigurationFromNDPRA

	// DHCPv6ManagedAddress indicates that addresses are available via DHCPv6.
	//
	// DHCPv6ManagedAddress also implies DHCPv6OtherConfigurations because DHCPv6
	// returns all available configuration information when serving addresses.
	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
)

func (DHCPv6ConfigurationFromNDPRA) String 

func (i DHCPv6ConfigurationFromNDPRA) String() string

type HandleRAsConfiguration 

type HandleRAsConfiguration int

HandleRAsConfiguration enumerates when RAs may be handled. 

const (
	// HandlingRAsDisabled indicates that Router Advertisements will not be
	// handled.
	HandlingRAsDisabled HandleRAsConfiguration = iota

	// HandlingRAsEnabledWhenForwardingDisabled indicates that router
	// advertisements will only be handled when forwarding is disabled.
	HandlingRAsEnabledWhenForwardingDisabled

	// HandlingRAsAlwaysEnabled indicates that Router Advertisements will always
	// be handled, even when forwarding is enabled.
	HandlingRAsAlwaysEnabled
)

func (HandleRAsConfiguration) String 

func (c HandleRAsConfiguration) String() string

String implements fmt.Stringer.

type MLDOptions 

type MLDOptions struct {
	// Enabled indicates whether MLD will be performed.
	//
	// When enabled, MLD may transmit MLD report and done messages when
	// joining and leaving multicast groups respectively, and handle incoming
	// MLD packets.
	//
	// This field is ignored and is always assumed to be false for interfaces
	// without neighbouring nodes (e.g. loopback).
	Enabled bool
}

MLDOptions holds options for MLD.

type NDPConfigurations 

type NDPConfigurations struct {
	// The number of Router Solicitation messages to send when the IPv6 endpoint
	// becomes enabled.
	//
	// Ignored unless configured to handle Router Advertisements.
	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 is the configuration for when Router Advertisements should be
	// handled.
	HandleRAs HandleRAsConfiguration

	// DiscoverDefaultRouters determines whether or not default routers are
	// discovered from Router Advertisements, as per RFC 4861 section 6. This
	// configuration is ignored if HandleRAs is false.
	DiscoverDefaultRouters bool

	// DiscoverOnLinkPrefixes determines whether or not on-link prefixes are
	// discovered from Router Advertisements' Prefix Information option, as per
	// RFC 4861 section 6. This configuration is ignored if HandleRAs is false.
	DiscoverOnLinkPrefixes bool

	// AutoGenGlobalAddresses determines whether or not an IPv6 endpoint performs
	// SLAAC to auto-generate global SLAAC addresses in response to Prefix
	// Information options, as per RFC 4862.
	//
	// 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 is made to resolve the conflict.
	AutoGenAddressConflictRetries uint8

	// AutoGenTempGlobalAddresses determines whether or not temporary SLAAC
	// addresses are generated for an IPv6 endpoint as part of SLAAC privacy
	// extensions, as per 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
}

NDPConfigurations is the NDP configurations for the netstack.

func DefaultNDPConfigurations 

func DefaultNDPConfigurations() NDPConfigurations

DefaultNDPConfigurations returns an NDPConfigurations populated with default values.

type NDPDispatcher 

type NDPDispatcher interface {
	// OnDuplicateAddressDetectionResult is called when the DAD process for an
	// address on a NIC completes.
	//
	// This function is not permitted to block indefinitely. This function
	// is also not permitted to call into the stack.
	OnDuplicateAddressDetectionResult(tcpip.NICID, tcpip.Address, stack.DADResult)

	// OnDefaultRouterDiscovered is 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(tcpip.NICID, tcpip.Address) bool

	// OnDefaultRouterInvalidated is 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(tcpip.NICID, tcpip.Address)

	// OnOnLinkPrefixDiscovered is 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(tcpip.NICID, tcpip.Subnet) bool

	// OnOnLinkPrefixInvalidated is 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(tcpip.NICID, tcpip.Subnet)

	// OnAutoGenAddress is called when a new prefix with its autonomous address-
	// configuration flag set is received and SLAAC was 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 is called when an auto-generated address (SLAAC)
	// is deprecated, but is still considered valid. Note, if an address is
	// invalidated at the same ime it is deprecated, the deprecation event may not
	// be received.
	//
	// This function is not permitted to block indefinitely. It must not
	// call functions on the stack itself.
	OnAutoGenAddressDeprecated(tcpip.NICID, tcpip.AddressWithPrefix)

	// OnAutoGenAddressInvalidated is called when an auto-generated address
	// (SLAAC) is invalidated.
	//
	// This function is not permitted to block indefinitely. It must not
	// call functions on the stack itself.
	OnAutoGenAddressInvalidated(tcpip.NICID, tcpip.AddressWithPrefix)

	// OnRecursiveDNSServerOption is called when the stack learns of DNS servers
	// through NDP. Note, the addresses 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 the lifetime (it may be increased,
	// decreased, or completely invalidated when the lifetime = 0).
	//
	// This function is not permitted to block indefinitely. It must not
	// call functions on the stack itself.
	OnRecursiveDNSServerOption(tcpip.NICID, []tcpip.Address, time.Duration)

	// OnDNSSearchListOption is called when the stack learns of DNS search lists
	// through NDP.
	//
	// 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 the lifetime (it may
	// be increased, decreased or completely invalidated when the lifetime = 0.
	OnDNSSearchListOption(tcpip.NICID, []string, time.Duration)

	// OnDHCPv6Configuration is called with an updated configuration that is
	// available via DHCPv6 for the passed NIC.
	//
	// This function is not permitted to block indefinitely. It must not
	// call functions on the stack itself.
	OnDHCPv6Configuration(tcpip.NICID, DHCPv6ConfigurationFromNDPRA)
}

NDPDispatcher is the interface integrators of netstack must implement to receive and handle NDP related events.

type NDPEndpoint 

type NDPEndpoint interface {
	// SetNDPConfigurations sets the NDP configurations.
	SetNDPConfigurations(NDPConfigurations)
}

NDPEndpoint is an endpoint that supports NDP.

type NICNameFromID 

type NICNameFromID func(tcpip.NICID, string) string

NICNameFromID is a function that returns a stable name for the specified NIC, even if different NIC IDs are used to refer to the same NIC in different program runs. It is used when generating opaque interface identifiers (IIDs). If the NIC was created with a name, it is passed to NICNameFromID.

NICNameFromID SHOULD return unique NIC names so unique opaque IIDs are generated for the same prefix on differnt NICs.

type OpaqueInterfaceIdentifierOptions 

type OpaqueInterfaceIdentifierOptions struct {
	// NICNameFromID is a function that returns a stable name for a specified NIC,
	// even if the NIC ID changes over time.
	//
	// Must be specified to generate the opaque IID.
	NICNameFromID NICNameFromID

	// SecretKey is a pseudo-random number used as the secret key when generating
	// opaque IIDs as defined by RFC 7217. The key SHOULD be at least
	// header.OpaqueIIDSecretKeyMinBytes bytes and MUST follow minimum randomness
	// requirements for security as outlined by RFC 4086. SecretKey MUST NOT
	// change between program runs, unless explicitly changed.
	//
	// OpaqueInterfaceIdentifierOptions takes ownership of SecretKey. SecretKey
	// MUST NOT be modified after Stack is created.
	//
	// May be nil, but a nil value is highly discouraged to maintain
	// some level of randomness between nodes.
	SecretKey []byte
}

OpaqueInterfaceIdentifierOptions holds the options related to the generation of opaque interface indentifiers (IIDs) as defined by RFC 7217.

type Options 

type Options struct {
	// NDPConfigs is the default NDP configurations used by interfaces.
	NDPConfigs NDPConfigurations

	// AutoGenLinkLocal determines whether or not the stack attempts to
	// auto-generate a link-local address for newly enabled non-loopback
	// NICs.
	//
	// Note, setting this to true does not mean that a link-local address is
	// assigned right away, or at all. If Duplicate Address Detection is enabled,
	// an address is only assigned if it successfully resolves. If it fails, no
	// further attempts are made to auto-generate a link-local adddress.
	//
	// The generated link-local address follows RFC 4291 Appendix A guidelines.
	AutoGenLinkLocal bool

	// NDPDisp is the NDP event dispatcher that an integrator can provide to
	// receive NDP related events.
	NDPDisp NDPDispatcher

	// OpaqueIIDOpts hold the options for generating opaque interface
	// identifiers (IIDs) as outlined by RFC 7217.
	OpaqueIIDOpts OpaqueInterfaceIdentifierOptions

	// TempIIDSeed is used to seed the initial temporary interface identifier
	// history value used to generate IIDs for temporary SLAAC addresses.
	//
	// Temporary SLAAC adresses are short-lived addresses which are unpredictable
	// and random from the perspective of other nodes on the network. It is
	// recommended that the seed be a random byte buffer of at least
	// header.IIDSize bytes to make sure that temporary SLAAC addresses are
	// sufficiently random. It should follow minimum randomness requirements for
	// security as outlined by RFC 4086.
	//
	// Note: using a nil value, the same seed across netstack program runs, or a
	// seed that is too small would reduce randomness and increase predictability,
	// defeating the purpose of temporary SLAAC addresses.
	TempIIDSeed []byte

	// MLD holds options for MLD.
	MLD MLDOptions

	// DADConfigs holds the default DAD configurations used by IPv6 endpoints.
	DADConfigs stack.DADConfigurations

	// AllowExternalLoopbackTraffic indicates that inbound loopback packets (i.e.
	// martian loopback packets) should be accepted.
	AllowExternalLoopbackTraffic bool
}

Options holds options to configure a new protocol.

type Stats 

type Stats struct {
	// IP holds IPv6 statistics.
	IP tcpip.IPStats

	// ICMP holds ICMPv6 statistics.
	ICMP tcpip.ICMPv6Stats

	// UnhandledRouterAdvertisements is the number of Router Advertisements that
	// were observed but not handled.
	UnhandledRouterAdvertisements *tcpip.StatCounter
}

Stats holds statistics related to the IPv6 protocol family.

func (*Stats) IPStats 

func (s *Stats) IPStats() *tcpip.IPStats

IPStats implements stack.IPNetworkEndointStats

func (*Stats) IsNetworkEndpointStats 

func (*Stats) IsNetworkEndpointStats()

IsNetworkEndpointStats implements stack.NetworkEndpointStats.

Source Files

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