stack

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Published: Nov 23, 2019 License: Apache-2.0 Imports: 20 Imported by: 135

Documentation

Overview

Package stack provides the glue between networking protocols and the consumers of the networking stack.

For consumers, the only function of interest is New(), everything else is provided by the tcpip/public package.

Index

Constants

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.
	//
	// Max = 10.
	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.
	//
	// Max = 10.
	MaxDiscoveredOnLinkPrefixes = 10
)
View Source
const (

	// DefaultTOS is the default type of service value for network endpoints.
	DefaultTOS = 0
)
View Source
const SoftwareGSOMaxSize = (1 << 16)

SoftwareGSOMaxSize is a maximum allowed size of a software GSO segment. This isn't a hard limit, because it is never set into packet headers.

Variables

This section is empty.

Functions

This section is empty.

Types

type ControlType

type ControlType int

ControlType is the type of network control message.

const (
	ControlPacketTooBig ControlType = iota
	ControlPortUnreachable
	ControlUnknown
)

The following are the allowed values for ControlType values.

type DirectionStats

type DirectionStats struct {
	Packets *tcpip.StatCounter
	Bytes   *tcpip.StatCounter
}

DirectionStats includes packet and byte counts.

type GSO

type GSO struct {
	// Type is one of GSONone, GSOTCPv4, etc.
	Type GSOType
	// NeedsCsum is set if the checksum offload is enabled.
	NeedsCsum bool
	// CsumOffset is offset after that to place checksum.
	CsumOffset uint16

	// Mss is maximum segment size.
	MSS uint16
	// L3Len is L3 (IP) header length.
	L3HdrLen uint16

	// MaxSize is maximum GSO packet size.
	MaxSize uint32
}

GSO contains generic segmentation offload properties.

+stateify savable

type GSOEndpoint

type GSOEndpoint interface {
	// GSOMaxSize returns the maximum GSO packet size.
	GSOMaxSize() uint32
}

GSOEndpoint provides access to GSO properties.

type GSOType

type GSOType int

GSOType is the type of GSO segments.

+stateify savable

const (
	GSONone GSOType = iota

	// Hardware GSO types:
	GSOTCPv4
	GSOTCPv6

	// GSOSW is used for software GSO segments which have to be sent by
	// endpoint.WritePackets.
	GSOSW
)

Types of gso segments.

type ICMPRateLimiter

type ICMPRateLimiter struct {
	*rate.Limiter
}

ICMPRateLimiter is a global rate limiter that controls the generation of ICMP messages generated by the stack.

func NewICMPRateLimiter

func NewICMPRateLimiter() *ICMPRateLimiter

NewICMPRateLimiter returns a global rate limiter for controlling the rate at which ICMP messages are generated by the stack.

type InjectableLinkEndpoint

type InjectableLinkEndpoint interface {
	LinkEndpoint

	// InjectInbound injects an inbound packet.
	InjectInbound(protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer)

	// InjectOutbound writes a fully formed outbound packet directly to the
	// link.
	//
	// dest is used by endpoints with multiple raw destinations.
	InjectOutbound(dest tcpip.Address, packet []byte) *tcpip.Error
}

InjectableLinkEndpoint is a LinkEndpoint where inbound packets are delivered via the Inject method.

type LinkAddressCache

type LinkAddressCache interface {
	// CheckLocalAddress determines if the given local address exists, and if it
	// does not exist.
	CheckLocalAddress(nicID tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) tcpip.NICID

	// AddLinkAddress adds a link address to the cache.
	AddLinkAddress(nicID tcpip.NICID, addr tcpip.Address, linkAddr tcpip.LinkAddress)

	// GetLinkAddress looks up the cache to translate address to link address (e.g. IP -> MAC).
	// If the LinkEndpoint requests address resolution and there is a LinkAddressResolver
	// registered with the network protocol, the cache attempts to resolve the address
	// and returns ErrWouldBlock. Waker is notified when address resolution is
	// complete (success or not).
	//
	// If address resolution is required, ErrNoLinkAddress and a notification channel is
	// returned for the top level caller to block. Channel is closed once address resolution
	// is complete (success or not).
	GetLinkAddress(nicID tcpip.NICID, addr, localAddr tcpip.Address, protocol tcpip.NetworkProtocolNumber, w *sleep.Waker) (tcpip.LinkAddress, <-chan struct{}, *tcpip.Error)

	// RemoveWaker removes a waker that has been added in GetLinkAddress().
	RemoveWaker(nicID tcpip.NICID, addr tcpip.Address, waker *sleep.Waker)
}

A LinkAddressCache caches link addresses.

type LinkAddressResolver

type LinkAddressResolver interface {
	// LinkAddressRequest sends a request for the LinkAddress of addr.
	// The request is sent on linkEP with localAddr as the source.
	//
	// A valid response will cause the discovery protocol's network
	// endpoint to call AddLinkAddress.
	LinkAddressRequest(addr, localAddr tcpip.Address, linkEP LinkEndpoint) *tcpip.Error

	// ResolveStaticAddress attempts to resolve address without sending
	// requests. It either resolves the name immediately or returns the
	// empty LinkAddress.
	//
	// It can be used to resolve broadcast addresses for example.
	ResolveStaticAddress(addr tcpip.Address) (tcpip.LinkAddress, bool)

	// LinkAddressProtocol returns the network protocol of the
	// addresses this this resolver can resolve.
	LinkAddressProtocol() tcpip.NetworkProtocolNumber
}

A LinkAddressResolver is an extension to a NetworkProtocol that can resolve link addresses.

type LinkEndpoint

type LinkEndpoint interface {
	// MTU is the maximum transmission unit for this endpoint. This is
	// usually dictated by the backing physical network; when such a
	// physical network doesn't exist, the limit is generally 64k, which
	// includes the maximum size of an IP packet.
	MTU() uint32

	// Capabilities returns the set of capabilities supported by the
	// endpoint.
	Capabilities() LinkEndpointCapabilities

	// MaxHeaderLength returns the maximum size the data link (and
	// lower level layers combined) headers can have. Higher levels use this
	// information to reserve space in the front of the packets they're
	// building.
	MaxHeaderLength() uint16

	// LinkAddress returns the link address (typically a MAC) of the
	// link endpoint.
	LinkAddress() tcpip.LinkAddress

	// WritePacket writes a packet with the given protocol through the
	// given route. It sets pkt.LinkHeader if a link layer header exists.
	// pkt.NetworkHeader and pkt.TransportHeader must have already been
	// set.
	//
	// To participate in transparent bridging, a LinkEndpoint implementation
	// should call eth.Encode with header.EthernetFields.SrcAddr set to
	// r.LocalLinkAddress if it is provided.
	WritePacket(r *Route, gso *GSO, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer) *tcpip.Error

	// WritePackets writes packets with the given protocol through the
	// given route.
	//
	// Right now, WritePackets is used only when the software segmentation
	// offload is enabled. If it will be used for something else, it may
	// require to change syscall filters.
	WritePackets(r *Route, gso *GSO, hdrs []PacketDescriptor, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) (int, *tcpip.Error)

	// WriteRawPacket writes a packet directly to the link. The packet
	// should already have an ethernet header.
	WriteRawPacket(vv buffer.VectorisedView) *tcpip.Error

	// Attach attaches the data link layer endpoint to the network-layer
	// dispatcher of the stack.
	Attach(dispatcher NetworkDispatcher)

	// IsAttached returns whether a NetworkDispatcher is attached to the
	// endpoint.
	IsAttached() bool

	// Wait waits for any worker goroutines owned by the endpoint to stop.
	//
	// For now, requesting that an endpoint's worker goroutine(s) stop is
	// implementation specific.
	//
	// Wait will not block if the endpoint hasn't started any goroutines
	// yet, even if it might later.
	Wait()
}

LinkEndpoint is the interface implemented by data link layer protocols (e.g., ethernet, loopback, raw) and used by network layer protocols to send packets out through the implementer's data link endpoint. When a link header exists, it sets each tcpip.PacketBuffer's LinkHeader field before passing it up the stack.

type LinkEndpointCapabilities

type LinkEndpointCapabilities uint

LinkEndpointCapabilities is the type associated with the capabilities supported by a link-layer endpoint. It is a set of bitfields.

const (
	CapabilityNone LinkEndpointCapabilities = 0
	// CapabilityTXChecksumOffload indicates that the link endpoint supports
	// checksum computation for outgoing packets and the stack can skip
	// computing checksums when sending packets.
	CapabilityTXChecksumOffload LinkEndpointCapabilities = 1 << iota
	// CapabilityRXChecksumOffload indicates that the link endpoint supports
	// checksum verification on received packets and that it's safe for the
	// stack to skip checksum verification.
	CapabilityRXChecksumOffload
	CapabilityResolutionRequired
	CapabilitySaveRestore
	CapabilityDisconnectOk
	CapabilityLoopback
	CapabilityHardwareGSO

	// CapabilitySoftwareGSO indicates the link endpoint supports of sending
	// multiple packets using a single call (LinkEndpoint.WritePackets).
	CapabilitySoftwareGSO
)

The following are the supported link endpoint capabilities.

type NDPConfigurations

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 0.5s.
	RetransmitTimer 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
}

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 {
	// OnDuplicateAddressDetectionStatus will be called when the DAD process
	// 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)

	// OnDefaultRouterDiscovered will be called when a new default router is
	// discovered. Implementations must return true along with a new valid
	// route table if the newly discovered router should be remembered. If
	// an implementation returns false, the second return value will be
	// ignored.
	//
	// 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, []tcpip.Route)

	// OnDefaultRouterInvalidated will be called when a discovered default
	// router is invalidated. Implementers must return a new valid route
	// table.
	//
	// 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) []tcpip.Route

	// OnOnLinkPrefixDiscovered will be called when a new on-link prefix is
	// discovered. Implementations must return true along with a new valid
	// route table if the newly discovered on-link prefix should be
	// remembered. If an implementation returns false, the second return
	// value will be ignored.
	//
	// 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, []tcpip.Route)

	// OnOnLinkPrefixInvalidated will be called when a discovered on-link
	// prefix is invalidated. Implementers must return a new valid route
	// table.
	//
	// 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) []tcpip.Route
}

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

type NIC

type NIC struct {
	// contains filtered or unexported fields
}

NIC represents a "network interface card" to which the networking stack is attached.

func (*NIC) AddAddress

func (n *NIC) AddAddress(protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior) *tcpip.Error

AddAddress adds a new address to n, so that it starts accepting packets targeted at the given address (and network protocol).

func (*NIC) AddAddressRange

func (n *NIC) AddAddressRange(protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet)

AddAddressRange adds a range of addresses to n, so that it starts accepting packets targeted at the given addresses and network protocol. The range is given by a subnet address, and all addresses contained in the subnet are used except for the subnet address itself and the subnet's broadcast address.

func (*NIC) AddressRanges

func (n *NIC) AddressRanges() []tcpip.Subnet

Subnets returns the Subnets associated with this NIC.

func (*NIC) AllAddresses

func (n *NIC) AllAddresses() []tcpip.ProtocolAddress

AllAddresses returns all addresses (primary and non-primary) associated with this NIC.

func (*NIC) DeliverNetworkPacket

func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer)

DeliverNetworkPacket finds the appropriate network protocol endpoint and hands the packet over for further processing. This function is called when the NIC receives a packet from the physical interface. Note that the ownership of the slice backing vv is retained by the caller. This rule applies only to the slice itself, not to the items of the slice; the ownership of the items is not retained by the caller.

func (*NIC) DeliverTransportControlPacket

func (n *NIC) DeliverTransportControlPacket(local, remote tcpip.Address, net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ ControlType, extra uint32, pkt tcpip.PacketBuffer)

DeliverTransportControlPacket delivers control packets to the appropriate transport protocol endpoint.

func (*NIC) DeliverTransportPacket

func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolNumber, pkt tcpip.PacketBuffer)

DeliverTransportPacket delivers the packets to the appropriate transport protocol endpoint.

func (*NIC) ID

func (n *NIC) ID() tcpip.NICID

ID returns the identifier of n.

func (*NIC) PrimaryAddresses

func (n *NIC) PrimaryAddresses() []tcpip.ProtocolAddress

PrimaryAddresses returns the primary addresses associated with this NIC.

func (*NIC) RemoveAddress

func (n *NIC) RemoveAddress(addr tcpip.Address) *tcpip.Error

RemoveAddress removes an address from n.

func (*NIC) RemoveAddressRange

func (n *NIC) RemoveAddressRange(subnet tcpip.Subnet)

RemoveAddressRange removes the given address range from n.

func (*NIC) Stack

func (n *NIC) Stack() *Stack

Stack returns the instance of the Stack that owns this NIC.

type NICInfo

type NICInfo struct {
	Name              string
	LinkAddress       tcpip.LinkAddress
	ProtocolAddresses []tcpip.ProtocolAddress

	// Flags indicate the state of the NIC.
	Flags NICStateFlags

	// MTU is the maximum transmission unit.
	MTU uint32

	Stats NICStats
}

NICInfo captures the name and addresses assigned to a NIC.

type NICStateFlags

type NICStateFlags struct {
	// Up indicates whether the interface is running.
	Up bool

	// Running indicates whether resources are allocated.
	Running bool

	// Promiscuous indicates whether the interface is in promiscuous mode.
	Promiscuous bool

	// Loopback indicates whether the interface is a loopback.
	Loopback bool
}

NICStateFlags holds information about the state of an NIC.

type NICStats

type NICStats struct {
	Tx DirectionStats
	Rx DirectionStats
}

NICStats includes transmitted and received stats.

type NetworkDispatcher

type NetworkDispatcher interface {
	// DeliverNetworkPacket finds the appropriate network protocol endpoint
	// and hands the packet over for further processing.
	//
	// pkt.LinkHeader may or may not be set before calling
	// DeliverNetworkPacket. Some packets do not have link headers (e.g.
	// packets sent via loopback), and won't have the field set.
	//
	// DeliverNetworkPacket takes ownership of pkt.
	DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer)
}

NetworkDispatcher contains the methods used by the network stack to deliver packets to the appropriate network endpoint after it has been handled by the data link layer.

type NetworkEndpoint

type NetworkEndpoint interface {
	// DefaultTTL is the default time-to-live value (or hop limit, in ipv6)
	// for this endpoint.
	DefaultTTL() uint8

	// MTU is the maximum transmission unit for this endpoint. This is
	// generally calculated as the MTU of the underlying data link endpoint
	// minus the network endpoint max header length.
	MTU() uint32

	// Capabilities returns the set of capabilities supported by the
	// underlying link-layer endpoint.
	Capabilities() LinkEndpointCapabilities

	// MaxHeaderLength returns the maximum size the network (and lower
	// level layers combined) headers can have. Higher levels use this
	// information to reserve space in the front of the packets they're
	// building.
	MaxHeaderLength() uint16

	// WritePacket writes a packet to the given destination address and
	// protocol. It sets pkt.NetworkHeader. pkt.TransportHeader must have
	// already been set.
	WritePacket(r *Route, gso *GSO, params NetworkHeaderParams, loop PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error

	// WritePackets writes packets to the given destination address and
	// protocol.
	WritePackets(r *Route, gso *GSO, hdrs []PacketDescriptor, payload buffer.VectorisedView, params NetworkHeaderParams, loop PacketLooping) (int, *tcpip.Error)

	// WriteHeaderIncludedPacket writes a packet that includes a network
	// header to the given destination address.
	WriteHeaderIncludedPacket(r *Route, loop PacketLooping, pkt tcpip.PacketBuffer) *tcpip.Error

	// ID returns the network protocol endpoint ID.
	ID() *NetworkEndpointID

	// PrefixLen returns the network endpoint's subnet prefix length in bits.
	PrefixLen() int

	// NICID returns the id of the NIC this endpoint belongs to.
	NICID() tcpip.NICID

	// HandlePacket is called by the link layer when new packets arrive to
	// this network endpoint. It sets pkt.NetworkHeader.
	//
	// HandlePacket takes ownership of pkt.
	HandlePacket(r *Route, pkt tcpip.PacketBuffer)

	// Close is called when the endpoint is reomved from a stack.
	Close()
}

NetworkEndpoint is the interface that needs to be implemented by endpoints of network layer protocols (e.g., ipv4, ipv6).

type NetworkEndpointID

type NetworkEndpointID struct {
	LocalAddress tcpip.Address
}

NetworkEndpointID is the identifier of a network layer protocol endpoint. Currently the local address is sufficient because all supported protocols (i.e., IPv4 and IPv6) have different sizes for their addresses.

type NetworkHeaderParams

type NetworkHeaderParams struct {
	// Protocol refers to the transport protocol number.
	Protocol tcpip.TransportProtocolNumber

	// TTL refers to Time To Live field of the IP-header.
	TTL uint8

	// TOS refers to TypeOfService or TrafficClass field of the IP-header.
	TOS uint8
}

NetworkHeaderParams are the header parameters given as input by the transport endpoint to the network.

type NetworkProtocol

type NetworkProtocol interface {
	// Number returns the network protocol number.
	Number() tcpip.NetworkProtocolNumber

	// MinimumPacketSize returns the minimum valid packet size of this
	// network protocol. The stack automatically drops any packets smaller
	// than this targeted at this protocol.
	MinimumPacketSize() int

	// DefaultPrefixLen returns the protocol's default prefix length.
	DefaultPrefixLen() int

	// ParsePorts returns the source and destination addresses stored in a
	// packet of this protocol.
	ParseAddresses(v buffer.View) (src, dst tcpip.Address)

	// NewEndpoint creates a new endpoint of this protocol.
	NewEndpoint(nicID tcpip.NICID, addrWithPrefix tcpip.AddressWithPrefix, linkAddrCache LinkAddressCache, dispatcher TransportDispatcher, sender LinkEndpoint) (NetworkEndpoint, *tcpip.Error)

	// SetOption allows enabling/disabling protocol specific features.
	// SetOption returns an error if the option is not supported or the
	// provided option value is invalid.
	SetOption(option interface{}) *tcpip.Error

	// Option allows retrieving protocol specific option values.
	// Option returns an error if the option is not supported or the
	// provided option value is invalid.
	Option(option interface{}) *tcpip.Error
}

NetworkProtocol is the interface that needs to be implemented by network protocols (e.g., ipv4, ipv6) that want to be part of the networking stack.

type Options

type Options struct {
	// NetworkProtocols lists the network protocols to enable.
	NetworkProtocols []NetworkProtocol

	// TransportProtocols lists the transport protocols to enable.
	TransportProtocols []TransportProtocol

	// Clock is an optional clock source used for timestampping packets.
	//
	// If no Clock is specified, the clock source will be time.Now.
	Clock tcpip.Clock

	// Stats are optional statistic counters.
	Stats tcpip.Stats

	// HandleLocal indicates whether packets destined to their source
	// should be handled by the stack internally (true) or outside the
	// stack (false).
	HandleLocal bool

	// UniqueID is an optional generator of unique identifiers.
	UniqueID UniqueID

	// NDPConfigs is the default NDP configurations used by interfaces.
	//
	// By default, NDPConfigs will have a zero value for its
	// DupAddrDetectTransmits field, implying that DAD will not be performed
	// before assigning an address to a NIC.
	NDPConfigs NDPConfigurations

	// AutoGenIPv6LinkLocal determins whether or not the stack will attempt
	// to auto-generate an IPv6 link-local address for newly enabled NICs.
	// Note, setting this to true does not mean that a link-local address
	// will be assigned right away, or at all. If Duplicate Address
	// Detection is enabled, an address will only be assigned if it
	// successfully resolves. If it fails, no further attempt will be made
	// to auto-generate an IPv6 link-local address.
	//
	// The generated link-local address will follow RFC 4291 Appendix A
	// guidelines.
	AutoGenIPv6LinkLocal bool

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

	// RawFactory produces raw endpoints. Raw endpoints are enabled only if
	// this is non-nil.
	RawFactory RawFactory
}

Options contains optional Stack configuration.

type PacketDescriptor

type PacketDescriptor struct {
	Hdr  buffer.Prependable
	Off  int
	Size int
}

PacketDescriptor is a packet descriptor which contains a packet header and offset and size of packet data in a payload view.

func NewPacketDescriptors

func NewPacketDescriptors(n int, hdrSize int) []PacketDescriptor

NewPacketDescriptors allocates a set of packet descriptors.

type PacketEndpoint

type PacketEndpoint interface {
	// HandlePacket is called by the stack when new packets arrive that
	// match the endpoint.
	//
	// Implementers should treat packet as immutable and should copy it
	// before before modification.
	//
	// linkHeader may have a length of 0, in which case the PacketEndpoint
	// should construct its own ethernet header for applications.
	//
	// HandlePacket takes ownership of pkt.
	HandlePacket(nicID tcpip.NICID, addr tcpip.LinkAddress, netProto tcpip.NetworkProtocolNumber, pkt tcpip.PacketBuffer)
}

PacketEndpoint is the interface that needs to be implemented by packet transport protocol endpoints. These endpoints receive link layer headers in addition to whatever they contain (usually network and transport layer headers and a payload).

type PacketLooping

type PacketLooping byte

PacketLooping specifies where an outbound packet should be sent.

const (
	// PacketOut indicates that the packet should be passed to the link
	// endpoint.
	PacketOut PacketLooping = 1 << iota

	// PacketLoop indicates that the packet should be handled locally.
	PacketLoop
)

type PrimaryEndpointBehavior

type PrimaryEndpointBehavior int

PrimaryEndpointBehavior is an enumeration of an endpoint's primacy behavior.

const (
	// CanBePrimaryEndpoint indicates the endpoint can be used as a primary
	// endpoint for new connections with no local address. This is the
	// default when calling NIC.AddAddress.
	CanBePrimaryEndpoint PrimaryEndpointBehavior = iota

	// FirstPrimaryEndpoint indicates the endpoint should be the first
	// primary endpoint considered. If there are multiple endpoints with
	// this behavior, the most recently-added one will be first.
	FirstPrimaryEndpoint

	// NeverPrimaryEndpoint indicates the endpoint should never be a
	// primary endpoint.
	NeverPrimaryEndpoint
)

type RawFactory

type RawFactory interface {
	// NewUnassociatedEndpoint produces endpoints for writing packets not
	// associated with a particular transport protocol. Such endpoints can
	// be used to write arbitrary packets that include the network header.
	NewUnassociatedEndpoint(stack *Stack, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)

	// NewPacketEndpoint produces endpoints for reading and writing packets
	// that include network and (when cooked is false) link layer headers.
	NewPacketEndpoint(stack *Stack, cooked bool, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)
}

RawFactory produces endpoints for writing various types of raw packets.

type RawTransportEndpoint

type RawTransportEndpoint interface {
	// HandlePacket is called by the stack when new packets arrive to
	// this transport endpoint. The packet contains all data from the link
	// layer up.
	//
	// HandlePacket takes ownership of pkt.
	HandlePacket(r *Route, pkt tcpip.PacketBuffer)
}

RawTransportEndpoint is the interface that needs to be implemented by raw transport protocol endpoints. RawTransportEndpoints receive the entire packet - including the network and transport headers - as delivered to netstack.

type RcvBufAutoTuneParams

type RcvBufAutoTuneParams struct {
	// MeasureTime is the time at which the current measurement
	// was started.
	MeasureTime time.Time

	// CopiedBytes is the number of bytes copied to user space since
	// this measure began.
	CopiedBytes int

	// PrevCopiedBytes is the number of bytes copied to user space in
	// the previous RTT period.
	PrevCopiedBytes int

	// RcvBufSize is the auto tuned receive buffer size.
	RcvBufSize int

	// RTT is the smoothed RTT as measured by observing the time between
	// when a byte is first acknowledged and the receipt of data that is at
	// least one window beyond the sequence number that was acknowledged.
	RTT time.Duration

	// RTTVar is the "round-trip time variation" as defined in section 2
	// of RFC6298.
	RTTVar time.Duration

	// RTTMeasureSeqNumber is the highest acceptable sequence number at the
	// time this RTT measurement period began.
	RTTMeasureSeqNumber seqnum.Value

	// RTTMeasureTime is the absolute time at which the current RTT
	// measurement period began.
	RTTMeasureTime time.Time

	// Disabled is true if an explicit receive buffer is set for the
	// endpoint.
	Disabled bool
}

RcvBufAutoTuneParams holds state related to TCP receive buffer auto-tuning.

type ResumableEndpoint

type ResumableEndpoint interface {
	// Resume resumes an endpoint after restore. This can be used to restart
	// background workers such as protocol goroutines. This must be called after
	// all indirect dependencies of the endpoint has been restored, which
	// generally implies at the end of the restore process.
	Resume(*Stack)
}

ResumableEndpoint is an endpoint that needs to be resumed after restore.

type Route

type Route struct {
	// RemoteAddress is the final destination of the route.
	RemoteAddress tcpip.Address

	// RemoteLinkAddress is the link-layer (MAC) address of the
	// final destination of the route.
	RemoteLinkAddress tcpip.LinkAddress

	// LocalAddress is the local address where the route starts.
	LocalAddress tcpip.Address

	// LocalLinkAddress is the link-layer (MAC) address of the
	// where the route starts.
	LocalLinkAddress tcpip.LinkAddress

	// NextHop is the next node in the path to the destination.
	NextHop tcpip.Address

	// NetProto is the network-layer protocol.
	NetProto tcpip.NetworkProtocolNumber

	// Loop controls where WritePacket should send packets.
	Loop PacketLooping
	// contains filtered or unexported fields
}

Route represents a route through the networking stack to a given destination.

func (*Route) Capabilities

func (r *Route) Capabilities() LinkEndpointCapabilities

Capabilities returns the link-layer capabilities of the route.

func (*Route) Clone

func (r *Route) Clone() Route

Clone Clone a route such that the original one can be released and the new one will remain valid.

func (*Route) DefaultTTL

func (r *Route) DefaultTTL() uint8

DefaultTTL returns the default TTL of the underlying network endpoint.

func (*Route) GSOMaxSize

func (r *Route) GSOMaxSize() uint32

GSOMaxSize returns the maximum GSO packet size.

func (*Route) IsResolutionRequired

func (r *Route) IsResolutionRequired() bool

IsResolutionRequired returns true if Resolve() must be called to resolve the link address before the this route can be written to.

func (*Route) MTU

func (r *Route) MTU() uint32

MTU returns the MTU of the underlying network endpoint.

func (*Route) MakeLoopedRoute

func (r *Route) MakeLoopedRoute() Route

MakeLoopedRoute duplicates the given route with special handling for routes used for sending multicast or broadcast packets. In those cases the multicast/broadcast address is the remote address when sending out, but for incoming (looped) packets it becomes the local address. Similarly, the local interface address that was the local address going out becomes the remote address coming in. This is different to unicast routes where local and remote addresses remain the same as they identify location (local vs remote) not direction (source vs destination).

func (*Route) MaxHeaderLength

func (r *Route) MaxHeaderLength() uint16

MaxHeaderLength forwards the call to the network endpoint's implementation.

func (*Route) NICID

func (r *Route) NICID() tcpip.NICID

NICID returns the id of the NIC from which this route originates.

func (*Route) PseudoHeaderChecksum

func (r *Route) PseudoHeaderChecksum(protocol tcpip.TransportProtocolNumber, totalLen uint16) uint16

PseudoHeaderChecksum forwards the call to the network endpoint's implementation.

func (*Route) Release

func (r *Route) Release()

Release frees all resources associated with the route.

func (*Route) RemoveWaker

func (r *Route) RemoveWaker(waker *sleep.Waker)

RemoveWaker removes a waker that has been added in Resolve().

func (*Route) Resolve

func (r *Route) Resolve(waker *sleep.Waker) (<-chan struct{}, *tcpip.Error)

Resolve attempts to resolve the link address if necessary. Returns ErrWouldBlock in case address resolution requires blocking, e.g. wait for ARP reply. Waker is notified when address resolution is complete (success or not).

If address resolution is required, ErrNoLinkAddress and a notification channel is returned for the top level caller to block. Channel is closed once address resolution is complete (success or not).

func (*Route) Stack

func (r *Route) Stack() *Stack

Stack returns the instance of the Stack that owns this route.

func (*Route) Stats

func (r *Route) Stats() tcpip.Stats

Stats returns a mutable copy of current stats.

func (*Route) WriteHeaderIncludedPacket

func (r *Route) WriteHeaderIncludedPacket(pkt tcpip.PacketBuffer) *tcpip.Error

WriteHeaderIncludedPacket writes a packet already containing a network header through the given route.

func (*Route) WritePacket

func (r *Route) WritePacket(gso *GSO, params NetworkHeaderParams, pkt tcpip.PacketBuffer) *tcpip.Error

WritePacket writes the packet through the given route.

func (*Route) WritePackets

func (r *Route) WritePackets(gso *GSO, hdrs []PacketDescriptor, payload buffer.VectorisedView, params NetworkHeaderParams) (int, *tcpip.Error)

WritePackets writes the set of packets through the given route.

type Stack

type Stack struct {
	*ports.PortManager
	// contains filtered or unexported fields
}

Stack is a networking stack, with all supported protocols, NICs, and route table.

func New

func New(opts Options) *Stack

New allocates a new networking stack with only the requested networking and transport protocols configured with default options.

Note, NDPConfigurations will be fixed before being used by the Stack. That is, if an invalid value was provided, it will be reset to the default value.

Protocol options can be changed by calling the SetNetworkProtocolOption/SetTransportProtocolOption methods provided by the stack. Please refer to individual protocol implementations as to what options are supported.

func (*Stack) AddAddress

func (s *Stack) AddAddress(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) *tcpip.Error

AddAddress adds a new network-layer address to the specified NIC.

func (*Stack) AddAddressRange

func (s *Stack) AddAddressRange(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, subnet tcpip.Subnet) *tcpip.Error

AddAddressRange adds a range of addresses to the specified NIC. The range is given by a subnet address, and all addresses contained in the subnet are used except for the subnet address itself and the subnet's broadcast address.

func (*Stack) AddAddressWithOptions

func (s *Stack) AddAddressWithOptions(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address, peb PrimaryEndpointBehavior) *tcpip.Error

AddAddressWithOptions is the same as AddAddress, but allows you to specify whether the new endpoint can be primary or not.

func (*Stack) AddLinkAddress

func (s *Stack) AddLinkAddress(nicID tcpip.NICID, addr tcpip.Address, linkAddr tcpip.LinkAddress)

AddLinkAddress adds a link address to the stack link cache.

func (*Stack) AddProtocolAddress

func (s *Stack) AddProtocolAddress(id tcpip.NICID, protocolAddress tcpip.ProtocolAddress) *tcpip.Error

AddProtocolAddress adds a new network-layer protocol address to the specified NIC.

func (*Stack) AddProtocolAddressWithOptions

func (s *Stack) AddProtocolAddressWithOptions(id tcpip.NICID, protocolAddress tcpip.ProtocolAddress, peb PrimaryEndpointBehavior) *tcpip.Error

AddProtocolAddressWithOptions is the same as AddProtocolAddress, but allows you to specify whether the new endpoint can be primary or not.

func (*Stack) AddTCPProbe

func (s *Stack) AddTCPProbe(probe TCPProbeFunc)

AddTCPProbe installs a probe function that will be invoked on every segment received by a given TCP endpoint. The probe function is passed a copy of the TCP endpoint state before and after processing of the segment.

NOTE: TCPProbe is added only to endpoints created after this call. Endpoints created prior to this call will not call the probe function.

Further, installing two different probes back to back can result in some endpoints calling the first one and some the second one. There is no guarantee provided on which probe will be invoked. Ideally this should only be called once per stack.

func (*Stack) AllAddresses

func (s *Stack) AllAddresses() map[tcpip.NICID][]tcpip.ProtocolAddress

AllAddresses returns a map of NICIDs to their protocol addresses (primary and non-primary).

func (*Stack) AllowICMPMessage

func (s *Stack) AllowICMPMessage() bool

AllowICMPMessage returns true if we the rate limiter allows at least one ICMP message to be sent at this instant.

func (*Stack) CheckLocalAddress

func (s *Stack) CheckLocalAddress(nicID tcpip.NICID, protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) tcpip.NICID

CheckLocalAddress determines if the given local address exists, and if it does, returns the id of the NIC it's bound to. Returns 0 if the address does not exist.

func (*Stack) CheckNIC

func (s *Stack) CheckNIC(id tcpip.NICID) bool

CheckNIC checks if a NIC is usable.

func (*Stack) CheckNetworkProtocol

func (s *Stack) CheckNetworkProtocol(protocol tcpip.NetworkProtocolNumber) bool

CheckNetworkProtocol checks if a given network protocol is enabled in the stack.

func (*Stack) CleanupEndpoints

func (s *Stack) CleanupEndpoints() []TransportEndpoint

CleanupEndpoints returns endpoints currently in the cleanup state.

func (*Stack) Close

func (s *Stack) Close()

Close closes all currently registered transport endpoints.

Endpoints created or modified during this call may not get closed.

func (*Stack) CompleteTransportEndpointCleanup

func (s *Stack) CompleteTransportEndpointCleanup(ep TransportEndpoint)

CompleteTransportEndpointCleanup removes the endpoint from the cleanup stage.

func (*Stack) CreateDisabledNIC

func (s *Stack) CreateDisabledNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error

CreateDisabledNIC creates a NIC with the provided id and link-layer endpoint, but leave it disable. Stack.EnableNIC must be called before the link-layer endpoint starts delivering packets to it.

func (*Stack) CreateDisabledNamedNIC

func (s *Stack) CreateDisabledNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error

CreateDisabledNamedNIC is a combination of CreateNamedNIC and CreateDisabledNIC.

func (*Stack) CreateNIC

func (s *Stack) CreateNIC(id tcpip.NICID, ep LinkEndpoint) *tcpip.Error

CreateNIC creates a NIC with the provided id and link-layer endpoint.

func (*Stack) CreateNamedLoopbackNIC

func (s *Stack) CreateNamedLoopbackNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error

CreateNamedLoopbackNIC creates a NIC with the provided id and link-layer endpoint, and a human-readable name.

func (*Stack) CreateNamedNIC

func (s *Stack) CreateNamedNIC(id tcpip.NICID, name string, ep LinkEndpoint) *tcpip.Error

CreateNamedNIC creates a NIC with the provided id and link-layer endpoint, and a human-readable name.

func (*Stack) DupTentativeAddrDetected

func (s *Stack) DupTentativeAddrDetected(id tcpip.NICID, addr tcpip.Address) *tcpip.Error

DupTentativeAddrDetected attempts to inform the NIC with ID id that a tentative addr on it is a duplicate on a link.

func (*Stack) EnableNIC

func (s *Stack) EnableNIC(id tcpip.NICID) *tcpip.Error

EnableNIC enables the given NIC so that the link-layer endpoint can start delivering packets to it.

func (*Stack) FindRoute

func (s *Stack) FindRoute(id tcpip.NICID, localAddr, remoteAddr tcpip.Address, netProto tcpip.NetworkProtocolNumber, multicastLoop bool) (Route, *tcpip.Error)

FindRoute creates a route to the given destination address, leaving through the given nic and local address (if provided).

func (*Stack) FindTransportEndpoint

func (s *Stack) FindTransportEndpoint(netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, id TransportEndpointID, r *Route) TransportEndpoint

FindTransportEndpoint finds an endpoint that most closely matches the provided id. If no endpoint is found it returns nil.

func (*Stack) Forwarding

func (s *Stack) Forwarding() bool

Forwarding returns if the packet forwarding between NICs is enabled.

func (*Stack) GetLinkAddress

func (s *Stack) GetLinkAddress(nicID tcpip.NICID, addr, localAddr tcpip.Address, protocol tcpip.NetworkProtocolNumber, waker *sleep.Waker) (tcpip.LinkAddress, <-chan struct{}, *tcpip.Error)

GetLinkAddress implements LinkAddressCache.GetLinkAddress.

func (*Stack) GetMainNICAddress

func (s *Stack) GetMainNICAddress(id tcpip.NICID, protocol tcpip.NetworkProtocolNumber) (tcpip.AddressWithPrefix, *tcpip.Error)

GetMainNICAddress returns the first primary address and prefix for the given NIC and protocol. Returns an error if the NIC doesn't exist and an empty value if the NIC doesn't have a primary address for the given protocol.

func (*Stack) GetRouteTable

func (s *Stack) GetRouteTable() []tcpip.Route

GetRouteTable returns the route table which is currently in use.

func (*Stack) GetTCPProbe

func (s *Stack) GetTCPProbe() TCPProbeFunc

GetTCPProbe returns the TCPProbeFunc if installed with AddTCPProbe, nil otherwise.

func (*Stack) HandleNDPRA

func (s *Stack) HandleNDPRA(id tcpip.NICID, ip tcpip.Address, ra header.NDPRouterAdvert) *tcpip.Error

HandleNDPRA provides a NIC with ID id a validated NDP Router Advertisement message that it needs to handle.

func (*Stack) ICMPBurst

func (s *Stack) ICMPBurst() int

ICMPBurst returns the maximum number of ICMP messages that can be sent in a single burst.

func (*Stack) ICMPLimit

func (s *Stack) ICMPLimit() rate.Limit

ICMPLimit returns the maximum number of ICMP messages that can be sent in one second.

func (*Stack) IPTables

func (s *Stack) IPTables() iptables.IPTables

IPTables returns the stack's iptables.

func (*Stack) IsAddrTentative

func (s *Stack) IsAddrTentative(id tcpip.NICID, addr tcpip.Address) (bool, *tcpip.Error)

IsAddrTentative returns true if addr is tentative on the NIC with ID id.

Note that if addr is not associated with a NIC with id ID, then this function will return false. It will only return true if the address is associated with the NIC AND it is tentative.

func (*Stack) JoinGroup

func (s *Stack) JoinGroup(protocol tcpip.NetworkProtocolNumber, nicID tcpip.NICID, multicastAddr tcpip.Address) *tcpip.Error

JoinGroup joins the given multicast group on the given NIC.

func (*Stack) LeaveGroup

func (s *Stack) LeaveGroup(protocol tcpip.NetworkProtocolNumber, nicID tcpip.NICID, multicastAddr tcpip.Address) *tcpip.Error

LeaveGroup leaves the given multicast group on the given NIC.

func (*Stack) NICAddressRanges

func (s *Stack) NICAddressRanges() map[tcpip.NICID][]tcpip.Subnet

NICSubnets returns a map of NICIDs to their associated subnets.

func (*Stack) NICInfo

func (s *Stack) NICInfo() map[tcpip.NICID]NICInfo

NICInfo returns a map of NICIDs to their associated information.

func (*Stack) NetworkProtocolInstance

func (s *Stack) NetworkProtocolInstance(num tcpip.NetworkProtocolNumber) NetworkProtocol

NetworkProtocolInstance returns the protocol instance in the stack for the specified network protocol. This method is public for protocol implementers and tests to use.

func (*Stack) NetworkProtocolOption

func (s *Stack) NetworkProtocolOption(network tcpip.NetworkProtocolNumber, option interface{}) *tcpip.Error

NetworkProtocolOption allows retrieving individual protocol level option values. This method returns an error if the protocol is not supported or option is not supported by the protocol implementation. e.g. var v ipv4.MyOption err := s.NetworkProtocolOption(tcpip.IPv4ProtocolNumber, &v) if err != nil {

...

}

func (*Stack) NewEndpoint

func (s *Stack) NewEndpoint(transport tcpip.TransportProtocolNumber, network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)

NewEndpoint creates a new transport layer endpoint of the given protocol.

func (*Stack) NewPacketEndpoint

func (s *Stack) NewPacketEndpoint(cooked bool, netProto tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)

NewPacketEndpoint creates a new packet endpoint listening for the given netProto.

func (*Stack) NewRawEndpoint

func (s *Stack) NewRawEndpoint(transport tcpip.TransportProtocolNumber, network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue, associated bool) (tcpip.Endpoint, *tcpip.Error)

NewRawEndpoint creates a new raw transport layer endpoint of the given protocol. Raw endpoints receive all traffic for a given protocol regardless of address.

func (*Stack) NowNanoseconds

func (s *Stack) NowNanoseconds() int64

NowNanoseconds implements tcpip.Clock.NowNanoseconds.

func (*Stack) RegisterPacketEndpoint

func (s *Stack) RegisterPacketEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, ep PacketEndpoint) *tcpip.Error

RegisterPacketEndpoint registers ep with the stack, causing it to receive all traffic of the specified netProto on the given NIC. If nicID is 0, it receives traffic from every NIC.

func (*Stack) RegisterRawTransportEndpoint

func (s *Stack) RegisterRawTransportEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, ep RawTransportEndpoint) *tcpip.Error

RegisterRawTransportEndpoint registers the given endpoint with the stack transport dispatcher. Received packets that match the provided transport protocol will be delivered to the given endpoint.

func (*Stack) RegisterRestoredEndpoint

func (s *Stack) RegisterRestoredEndpoint(e ResumableEndpoint)

RegisterRestoredEndpoint records e as an endpoint that has been restored on this stack.

func (*Stack) RegisterTransportEndpoint

func (s *Stack) RegisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, reusePort bool, bindToDevice tcpip.NICID) *tcpip.Error

RegisterTransportEndpoint registers the given endpoint with the stack transport dispatcher. Received packets that match the provided id will be delivered to the given endpoint; specifying a nic is optional, but nic-specific IDs have precedence over global ones.

func (*Stack) RegisteredEndpoints

func (s *Stack) RegisteredEndpoints() []TransportEndpoint

RegisteredEndpoints returns all endpoints which are currently registered.

func (*Stack) RemoveAddress

func (s *Stack) RemoveAddress(id tcpip.NICID, addr tcpip.Address) *tcpip.Error

RemoveAddress removes an existing network-layer address from the specified NIC.

func (*Stack) RemoveAddressRange

func (s *Stack) RemoveAddressRange(id tcpip.NICID, subnet tcpip.Subnet) *tcpip.Error

RemoveAddressRange removes the range of addresses from the specified NIC.

func (*Stack) RemoveTCPProbe

func (s *Stack) RemoveTCPProbe()

RemoveTCPProbe removes an installed TCP probe.

NOTE: This only ensures that endpoints created after this call do not have a probe attached. Endpoints already created will continue to invoke TCP probe.

func (*Stack) RemoveWaker

func (s *Stack) RemoveWaker(nicID tcpip.NICID, addr tcpip.Address, waker *sleep.Waker)

RemoveWaker implements LinkAddressCache.RemoveWaker.

func (*Stack) RestoreCleanupEndpoints

func (s *Stack) RestoreCleanupEndpoints(es []TransportEndpoint)

RestoreCleanupEndpoints adds endpoints to cleanup tracking. This is useful for restoring a stack after a save.

func (*Stack) Resume

func (s *Stack) Resume()

Resume restarts the stack after a restore. This must be called after the entire system has been restored.

func (*Stack) Seed

func (s *Stack) Seed() uint32

Seed returns a 32 bit value that can be used as a seed value for port picking, ISN generation etc.

NOTE: The seed is generated once during stack initialization only.

func (*Stack) SetForwarding

func (s *Stack) SetForwarding(enable bool)

SetForwarding enables or disables the packet forwarding between NICs.

func (*Stack) SetICMPBurst

func (s *Stack) SetICMPBurst(burst int)

SetICMPBurst sets the maximum number of ICMP messages that can be sent in a single burst.

func (*Stack) SetICMPLimit

func (s *Stack) SetICMPLimit(newLimit rate.Limit)

SetICMPLimit sets the maximum number of ICMP messages that be sent in one second.

func (*Stack) SetIPTables

func (s *Stack) SetIPTables(ipt iptables.IPTables)

SetIPTables sets the stack's iptables.

func (*Stack) SetNDPConfigurations

func (s *Stack) SetNDPConfigurations(id tcpip.NICID, c NDPConfigurations) *tcpip.Error

SetNDPConfigurations sets the per-interface NDP configurations on the NIC with ID id to c.

Note, if c contains invalid NDP configuration values, it will be fixed to use default values for the erroneous values.

func (*Stack) SetNetworkProtocolOption

func (s *Stack) SetNetworkProtocolOption(network tcpip.NetworkProtocolNumber, option interface{}) *tcpip.Error

SetNetworkProtocolOption allows configuring individual protocol level options. This method returns an error if the protocol is not supported or option is not supported by the protocol implementation or the provided value is incorrect.

func (*Stack) SetPromiscuousMode

func (s *Stack) SetPromiscuousMode(nicID tcpip.NICID, enable bool) *tcpip.Error

SetPromiscuousMode enables or disables promiscuous mode in the given NIC.

func (*Stack) SetRouteTable

func (s *Stack) SetRouteTable(table []tcpip.Route)

SetRouteTable assigns the route table to be used by this stack. It specifies which NIC to use for given destination address ranges.

func (*Stack) SetSpoofing

func (s *Stack) SetSpoofing(nicID tcpip.NICID, enable bool) *tcpip.Error

SetSpoofing enables or disables address spoofing in the given NIC, allowing endpoints to bind to any address in the NIC.

func (*Stack) SetTransportProtocolHandler

func (s *Stack) SetTransportProtocolHandler(p tcpip.TransportProtocolNumber, h func(*Route, TransportEndpointID, tcpip.PacketBuffer) bool)

SetTransportProtocolHandler sets the per-stack default handler for the given protocol.

It must be called only during initialization of the stack. Changing it as the stack is operating is not supported.

func (*Stack) SetTransportProtocolOption

func (s *Stack) SetTransportProtocolOption(transport tcpip.TransportProtocolNumber, option interface{}) *tcpip.Error

SetTransportProtocolOption allows configuring individual protocol level options. This method returns an error if the protocol is not supported or option is not supported by the protocol implementation or the provided value is incorrect.

func (*Stack) StartTransportEndpointCleanup

func (s *Stack) StartTransportEndpointCleanup(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, bindToDevice tcpip.NICID)

StartTransportEndpointCleanup removes the endpoint with the given id from the stack transport dispatcher. It also transitions it to the cleanup stage.

func (*Stack) Stats

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

Stats returns a mutable copy of the current stats.

This is not generally exported via the public interface, but is available internally.

func (*Stack) TransportProtocolInstance

func (s *Stack) TransportProtocolInstance(num tcpip.TransportProtocolNumber) TransportProtocol

TransportProtocolInstance returns the protocol instance in the stack for the specified transport protocol. This method is public for protocol implementers and tests to use.

func (*Stack) TransportProtocolOption

func (s *Stack) TransportProtocolOption(transport tcpip.TransportProtocolNumber, option interface{}) *tcpip.Error

TransportProtocolOption allows retrieving individual protocol level option values. This method returns an error if the protocol is not supported or option is not supported by the protocol implementation. var v tcp.SACKEnabled if err := s.TransportProtocolOption(tcpip.TCPProtocolNumber, &v); err != nil {

...

}

func (*Stack) UniqueID

func (s *Stack) UniqueID() uint64

UniqueID returns a unique identifier.

func (*Stack) UnregisterPacketEndpoint

func (s *Stack) UnregisterPacketEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, ep PacketEndpoint)

UnregisterPacketEndpoint unregisters ep for packets of the specified netProto from the specified NIC. If nicID is 0, ep is unregistered from all NICs.

func (*Stack) UnregisterRawTransportEndpoint

func (s *Stack) UnregisterRawTransportEndpoint(nicID tcpip.NICID, netProto tcpip.NetworkProtocolNumber, transProto tcpip.TransportProtocolNumber, ep RawTransportEndpoint)

UnregisterRawTransportEndpoint removes the endpoint for the transport protocol from the stack transport dispatcher.

func (*Stack) UnregisterTransportEndpoint

func (s *Stack) UnregisterTransportEndpoint(nicID tcpip.NICID, netProtos []tcpip.NetworkProtocolNumber, protocol tcpip.TransportProtocolNumber, id TransportEndpointID, ep TransportEndpoint, bindToDevice tcpip.NICID)

UnregisterTransportEndpoint removes the endpoint with the given id from the stack transport dispatcher.

func (*Stack) Wait

func (s *Stack) Wait()

Wait waits for all transport and link endpoints to halt their worker goroutines.

Endpoints created or modified during this call may not get waited on.

Note that link endpoints must be stopped via an implementation specific mechanism.

func (*Stack) WritePacket

func (s *Stack) WritePacket(nicID tcpip.NICID, dst tcpip.LinkAddress, netProto tcpip.NetworkProtocolNumber, payload buffer.VectorisedView) *tcpip.Error

WritePacket writes data directly to the specified NIC. It adds an ethernet header based on the arguments.

func (*Stack) WriteRawPacket

func (s *Stack) WriteRawPacket(nicID tcpip.NICID, payload buffer.VectorisedView) *tcpip.Error

WriteRawPacket writes data directly to the specified NIC without adding any headers.

type TCPCubicState

type TCPCubicState struct {
	WLastMax                float64
	WMax                    float64
	T                       time.Time
	TimeSinceLastCongestion time.Duration
	C                       float64
	K                       float64
	Beta                    float64
	WC                      float64
	WEst                    float64
}

TCPCubicState is used to hold a copy of the internal cubic state when the TCPProbeFunc is invoked.

type TCPEndpointID

type TCPEndpointID struct {
	// LocalPort is the local port associated with the endpoint.
	LocalPort uint16

	// LocalAddress is the local [network layer] address associated with
	// the endpoint.
	LocalAddress tcpip.Address

	// RemotePort is the remote port associated with the endpoint.
	RemotePort uint16

	// RemoteAddress it the remote [network layer] address associated with
	// the endpoint.
	RemoteAddress tcpip.Address
}

TCPEndpointID is the unique 4 tuple that identifies a given endpoint.

type TCPEndpointState

type TCPEndpointState struct {
	// ID is a copy of the TransportEndpointID for the endpoint.
	ID TCPEndpointID

	// SegTime denotes the absolute time when this segment was received.
	SegTime time.Time

	// RcvBufSize is the size of the receive socket buffer for the endpoint.
	RcvBufSize int

	// RcvBufUsed is the amount of bytes actually held in the receive socket
	// buffer for the endpoint.
	RcvBufUsed int

	// RcvBufAutoTuneParams is used to hold state variables to compute
	// the auto tuned receive buffer size.
	RcvAutoParams RcvBufAutoTuneParams

	// RcvClosed if true, indicates the endpoint has been closed for reading.
	RcvClosed bool

	// SendTSOk is used to indicate when the TS Option has been negotiated.
	// When sendTSOk is true every non-RST segment should carry a TS as per
	// RFC7323#section-1.1.
	SendTSOk bool

	// RecentTS is the timestamp that should be sent in the TSEcr field of
	// the timestamp for future segments sent by the endpoint. This field is
	// updated if required when a new segment is received by this endpoint.
	RecentTS uint32

	// TSOffset is a randomized offset added to the value of the TSVal field
	// in the timestamp option.
	TSOffset uint32

	// SACKPermitted is set to true if the peer sends the TCPSACKPermitted
	// option in the SYN/SYN-ACK.
	SACKPermitted bool

	// SACK holds TCP SACK related information for this endpoint.
	SACK TCPSACKInfo

	// SndBufSize is the size of the socket send buffer.
	SndBufSize int

	// SndBufUsed is the number of bytes held in the socket send buffer.
	SndBufUsed int

	// SndClosed indicates that the endpoint has been closed for sends.
	SndClosed bool

	// SndBufInQueue is the number of bytes in the send queue.
	SndBufInQueue seqnum.Size

	// PacketTooBigCount is used to notify the main protocol routine how
	// many times a "packet too big" control packet is received.
	PacketTooBigCount int

	// SndMTU is the smallest MTU seen in the control packets received.
	SndMTU int

	// Receiver holds variables related to the TCP receiver for the endpoint.
	Receiver TCPReceiverState

	// Sender holds state related to the TCP Sender for the endpoint.
	Sender TCPSenderState
}

TCPEndpointState is a copy of the internal state of a TCP endpoint.

type TCPFastRecoveryState

type TCPFastRecoveryState struct {
	// Active if true indicates the endpoint is in fast recovery.
	Active bool

	// First is the first unacknowledged sequence number being recovered.
	First seqnum.Value

	// Last is the 'recover' sequence number that indicates the point at
	// which we should exit recovery barring any timeouts etc.
	Last seqnum.Value

	// MaxCwnd is the maximum value we are permitted to grow the congestion
	// window during recovery. This is set at the time we enter recovery.
	MaxCwnd int

	// HighRxt is the highest sequence number which has been retransmitted
	// during the current loss recovery phase.
	// See: RFC 6675 Section 2 for details.
	HighRxt seqnum.Value

	// RescueRxt is the highest sequence number which has been
	// optimistically retransmitted to prevent stalling of the ACK clock
	// when there is loss at the end of the window and no new data is
	// available for transmission.
	// See: RFC 6675 Section 2 for details.
	RescueRxt seqnum.Value
}

TCPFastRecoveryState holds a copy of the internal fast recovery state of a TCP endpoint.

type TCPProbeFunc

type TCPProbeFunc func(s TCPEndpointState)

TCPProbeFunc is the expected function type for a TCP probe function to be passed to stack.AddTCPProbe.

type TCPReceiverState

type TCPReceiverState struct {
	// RcvNxt is the TCP variable RCV.NXT.
	RcvNxt seqnum.Value

	// RcvAcc is the TCP variable RCV.ACC.
	RcvAcc seqnum.Value

	// RcvWndScale is the window scaling to use for inbound segments.
	RcvWndScale uint8

	// PendingBufUsed is the number of bytes pending in the receive
	// queue.
	PendingBufUsed seqnum.Size

	// PendingBufSize is the size of the socket receive buffer.
	PendingBufSize seqnum.Size
}

TCPReceiverState holds a copy of the internal state of the receiver for a given TCP endpoint.

type TCPSACKInfo

type TCPSACKInfo struct {
	// Blocks is the list of SACK Blocks that identify the out of order segments
	// held by a given TCP endpoint.
	Blocks []header.SACKBlock

	// ReceivedBlocks are the SACK blocks received by this endpoint
	// from the peer endpoint.
	ReceivedBlocks []header.SACKBlock

	// MaxSACKED is the highest sequence number that has been SACKED
	// by the peer.
	MaxSACKED seqnum.Value
}

TCPSACKInfo holds TCP SACK related information for a given TCP endpoint.

type TCPSenderState

type TCPSenderState struct {
	// LastSendTime is the time at which we sent the last segment.
	LastSendTime time.Time

	// DupAckCount is the number of Duplicate ACK's received.
	DupAckCount int

	// SndCwnd is the size of the sending congestion window in packets.
	SndCwnd int

	// Ssthresh is the slow start threshold in packets.
	Ssthresh int

	// SndCAAckCount is the number of packets consumed in congestion
	// avoidance mode.
	SndCAAckCount int

	// Outstanding is the number of packets in flight.
	Outstanding int

	// SndWnd is the send window size in bytes.
	SndWnd seqnum.Size

	// SndUna is the next unacknowledged sequence number.
	SndUna seqnum.Value

	// SndNxt is the sequence number of the next segment to be sent.
	SndNxt seqnum.Value

	// RTTMeasureSeqNum is the sequence number being used for the latest RTT
	// measurement.
	RTTMeasureSeqNum seqnum.Value

	// RTTMeasureTime is the time when the RTTMeasureSeqNum was sent.
	RTTMeasureTime time.Time

	// Closed indicates that the caller has closed the endpoint for sending.
	Closed bool

	// SRTT is the smoothed round-trip time as defined in section 2 of
	// RFC 6298.
	SRTT time.Duration

	// RTO is the retransmit timeout as defined in section of 2 of RFC 6298.
	RTO time.Duration

	// RTTVar is the round-trip time variation as defined in section 2 of
	// RFC 6298.
	RTTVar time.Duration

	// SRTTInited if true indicates take a valid RTT measurement has been
	// completed.
	SRTTInited bool

	// MaxPayloadSize is the maximum size of the payload of a given segment.
	// It is initialized on demand.
	MaxPayloadSize int

	// SndWndScale is the number of bits to shift left when reading the send
	// window size from a segment.
	SndWndScale uint8

	// MaxSentAck is the highest acknowledgement number sent till now.
	MaxSentAck seqnum.Value

	// FastRecovery holds the fast recovery state for the endpoint.
	FastRecovery TCPFastRecoveryState

	// Cubic holds the state related to CUBIC congestion control.
	Cubic TCPCubicState
}

TCPSenderState holds a copy of the internal state of the sender for a given TCP Endpoint.

type TransportDispatcher

type TransportDispatcher interface {
	// DeliverTransportPacket delivers packets to the appropriate
	// transport protocol endpoint.
	//
	// pkt.NetworkHeader must be set before calling DeliverTransportPacket.
	//
	// DeliverTransportPacket takes ownership of pkt.
	DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolNumber, pkt tcpip.PacketBuffer)

	// DeliverTransportControlPacket delivers control packets to the
	// appropriate transport protocol endpoint.
	//
	// pkt.NetworkHeader must be set before calling
	// DeliverTransportControlPacket.
	//
	// DeliverTransportControlPacket takes ownership of pkt.
	DeliverTransportControlPacket(local, remote tcpip.Address, net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ ControlType, extra uint32, pkt tcpip.PacketBuffer)
}

TransportDispatcher contains the methods used by the network stack to deliver packets to the appropriate transport endpoint after it has been handled by the network layer.

type TransportEndpoint

type TransportEndpoint interface {
	// UniqueID returns an unique ID for this transport endpoint.
	UniqueID() uint64

	// HandlePacket is called by the stack when new packets arrive to
	// this transport endpoint. It sets pkt.TransportHeader.
	//
	// HandlePacket takes ownership of pkt.
	HandlePacket(r *Route, id TransportEndpointID, pkt tcpip.PacketBuffer)

	// HandleControlPacket is called by the stack when new control (e.g.
	// ICMP) packets arrive to this transport endpoint.
	// HandleControlPacket takes ownership of pkt.
	HandleControlPacket(id TransportEndpointID, typ ControlType, extra uint32, pkt tcpip.PacketBuffer)

	// Close puts the endpoint in a closed state and frees all resources
	// associated with it. This cleanup may happen asynchronously. Wait can
	// be used to block on this asynchronous cleanup.
	Close()

	// Wait waits for any worker goroutines owned by the endpoint to stop.
	//
	// An endpoint can be requested to stop its worker goroutines by calling
	// its Close method.
	//
	// Wait will not block if the endpoint hasn't started any goroutines
	// yet, even if it might later.
	Wait()
}

TransportEndpoint is the interface that needs to be implemented by transport protocol (e.g., tcp, udp) endpoints that can handle packets.

type TransportEndpointID

type TransportEndpointID struct {
	// LocalPort is the local port associated with the endpoint.
	LocalPort uint16

	// LocalAddress is the local [network layer] address associated with
	// the endpoint.
	LocalAddress tcpip.Address

	// RemotePort is the remote port associated with the endpoint.
	RemotePort uint16

	// RemoteAddress it the remote [network layer] address associated with
	// the endpoint.
	RemoteAddress tcpip.Address
}

TransportEndpointID is the identifier of a transport layer protocol endpoint.

+stateify savable

type TransportEndpointInfo

type TransportEndpointInfo struct {
	NetProto   tcpip.NetworkProtocolNumber
	TransProto tcpip.TransportProtocolNumber

	ID TransportEndpointID
	// BindNICID and bindAddr are set via calls to Bind(). They are used to
	// reject attempts to send data or connect via a different NIC or
	// address
	BindNICID tcpip.NICID
	BindAddr  tcpip.Address
	// RegisterNICID is the default NICID registered as a side-effect of
	// connect or datagram write.
	RegisterNICID tcpip.NICID
}

TransportEndpointInfo holds useful information about a transport endpoint which can be queried by monitoring tools.

+stateify savable

func (*TransportEndpointInfo) IsEndpointInfo

func (*TransportEndpointInfo) IsEndpointInfo()

IsEndpointInfo is an empty method to implement the tcpip.EndpointInfo marker interface.

type TransportProtocol

type TransportProtocol interface {
	// Number returns the transport protocol number.
	Number() tcpip.TransportProtocolNumber

	// NewEndpoint creates a new endpoint of the transport protocol.
	NewEndpoint(stack *Stack, netProto tcpip.NetworkProtocolNumber, waitQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)

	// NewRawEndpoint creates a new raw endpoint of the transport protocol.
	NewRawEndpoint(stack *Stack, netProto tcpip.NetworkProtocolNumber, waitQueue *waiter.Queue) (tcpip.Endpoint, *tcpip.Error)

	// MinimumPacketSize returns the minimum valid packet size of this
	// transport protocol. The stack automatically drops any packets smaller
	// than this targeted at this protocol.
	MinimumPacketSize() int

	// ParsePorts returns the source and destination ports stored in a
	// packet of this protocol.
	ParsePorts(v buffer.View) (src, dst uint16, err *tcpip.Error)

	// HandleUnknownDestinationPacket handles packets targeted at this
	// protocol but that don't match any existing endpoint. For example,
	// it is targeted at a port that have no listeners.
	//
	// The return value indicates whether the packet was well-formed (for
	// stats purposes only).
	//
	// HandleUnknownDestinationPacket takes ownership of pkt.
	HandleUnknownDestinationPacket(r *Route, id TransportEndpointID, pkt tcpip.PacketBuffer) bool

	// SetOption allows enabling/disabling protocol specific features.
	// SetOption returns an error if the option is not supported or the
	// provided option value is invalid.
	SetOption(option interface{}) *tcpip.Error

	// Option allows retrieving protocol specific option values.
	// Option returns an error if the option is not supported or the
	// provided option value is invalid.
	Option(option interface{}) *tcpip.Error
}

TransportProtocol is the interface that needs to be implemented by transport protocols (e.g., tcp, udp) that want to be part of the networking stack.

type UniqueID

type UniqueID interface {
	UniqueID() uint64
}

UniqueID is an abstract generator of unique identifiers.

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