ipv6

type DHCPv6ConfigurationFromNDPRA int

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
}

type NDPConfigurations struct {
	// The number of Neighbor Solicitation messages to send when doing
	// Duplicate Address Detection for a tentative address.
	//
	// Note, a value of zero effectively disables DAD.
	DupAddrDetectTransmits uint8

	// The amount of time to wait between sending Neighbor solicitation
	// messages.
	//
	// Must be greater than or equal to 1ms.
	RetransmitTimer time.Duration

	// The number of Router Solicitation messages to send when the IPv6 endpoint
	// 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 are processed.
	HandleRAs bool

	// 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
}

type NDPDispatcher interface {
	// OnDuplicateAddressDetectionStatus is called when the DAD process for an
	// address (addr) on a NIC (with ID nicID) completes. resolved is 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 is set and resolved must be ignored.
	//
	// 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 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(nicID tcpip.NICID, addr 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(nicID tcpip.NICID, addr 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(nicID tcpip.NICID, prefix 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(nicID tcpip.NICID, prefix 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 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 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 lifetime (it may
	// be increased, decreased or completely invalidated when lifetime = 0.
	OnDNSSearchListOption(nicID tcpip.NICID, domainNames []string, lifetime 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)
}

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

type NICNameFromID func(tcpip.NICID, string) string

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
}

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
}

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

	// ICMP holds ICMPv6 statistics.
	ICMP tcpip.ICMPv6Stats
}