stack

package
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 Go to latest Published: Apr 29, 2019 License: Apache-2.0 Imports: 15 Imported by: 3

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.

For protocol implementers, RegisterTransportProtocolFactory() and RegisterNetworkProtocolFactory() are used to register protocol factories with the stack, which will then be used to instantiate protocol objects when consumers interact with the stack.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func RegisterLinkEndpoint 

func RegisterLinkEndpoint(linkEP LinkEndpoint) tcpip.LinkEndpointID

RegisterLinkEndpoint register a link-layer protocol endpoint and returns an ID that can be used to refer to it.

func RegisterNetworkProtocolFactory 

func RegisterNetworkProtocolFactory(name string, p NetworkProtocolFactory)

RegisterNetworkProtocolFactory registers a new network protocol factory with the stack so that it becomes available to users of the stack. This function is intended to be called by init() functions of the protocols.

func RegisterTransportProtocolFactory 

func RegisterTransportProtocolFactory(name string, p TransportProtocolFactory)

RegisterTransportProtocolFactory registers a new transport protocol factory with the stack so that it becomes available to users of the stack. This function is intended to be called by init() functions of the protocols.

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
	GSOTCPv4
	GSOTCPv6
)

Types of gso segments.

type InjectableLinkEndpoint 

type InjectableLinkEndpoint interface {
	LinkEndpoint

	// Inject injects an inbound packet.
	Inject(protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView)

	// WriteRawPacket writes a fully formed outbound packet directly to the link.
	//
	// dest is used by endpoints with multiple raw destinations.
	WriteRawPacket(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.
	//
	// 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, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.NetworkProtocolNumber) *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
}

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.

func FindLinkEndpoint 

func FindLinkEndpoint(id tcpip.LinkEndpointID) LinkEndpoint

FindLinkEndpoint finds the link endpoint associated with the given ID.

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
	CapabilityGSO
)

The following are the supported link endpoint capabilities.

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(protocol tcpip.NetworkProtocolNumber, addr tcpip.Address) *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) AddAddressWithOptions 

func (n *NIC) AddAddressWithOptions(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 (*NIC) AddSubnet 

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

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

func (*NIC) Addresses 

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

Addresses returns the addresses associated with this NIC.

func (*NIC) ContainsSubnet 

func (n *NIC) ContainsSubnet(subnet tcpip.Subnet) bool

ContainsSubnet reports whether this NIC contains the given subnet.

func (*NIC) DeliverNetworkPacket 

func (n *NIC) DeliverNetworkPacket(linkEP LinkEndpoint, remote, _ tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView)

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, vv buffer.VectorisedView)

DeliverTransportControlPacket delivers control packets to the appropriate transport protocol endpoint.

func (*NIC) DeliverTransportPacket 

func (n *NIC) DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolNumber, netHeader buffer.View, vv buffer.VectorisedView)

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) RemoveAddress 

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

RemoveAddress removes an address from n.

func (*NIC) RemoveSubnet 

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

RemoveSubnet removes the given subnet from n.

func (*NIC) Subnets 

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

Subnets returns the Subnets associated with 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.
	DeliverNetworkPacket(linkEP LinkEndpoint, remote, local tcpip.LinkAddress, protocol tcpip.NetworkProtocolNumber, vv buffer.VectorisedView)
}

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.
	WritePacket(r *Route, gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8, loop PacketLooping) *tcpip.Error

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

	// 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.
	HandlePacket(r *Route, vv buffer.VectorisedView)

	// 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 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

	// 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, addr tcpip.Address, 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 NetworkProtocolFactory 

type NetworkProtocolFactory func() NetworkProtocol

NetworkProtocolFactory provides methods to be used by the stack to instantiate network protocols.

type Options 

type Options struct {
	// 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

	// Raw indicates whether raw sockets may be created.
	Raw bool
}

Options contains optional Stack configuration.

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 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(r *Route, netHeader buffer.View, packet buffer.VectorisedView)
}

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

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
	// 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) 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) Stats 

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

Stats returns a mutable copy of current stats.

func (*Route) WritePacket 

func (r *Route) WritePacket(gso *GSO, hdr buffer.Prependable, payload buffer.VectorisedView, protocol tcpip.TransportProtocolNumber, ttl uint8) *tcpip.Error

WritePacket writes the packet 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(network []string, transport []string, opts Options) *Stack

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

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) 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) AddSubnet 

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

AddSubnet adds a subnet range to the specified NIC.

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.

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) 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) ContainsSubnet 

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

ContainsSubnet reports whether the specified NIC contains the specified subnet.

func (*Stack) CreateDisabledNIC 

func (s *Stack) CreateDisabledNIC(id tcpip.NICID, linkEP tcpip.LinkEndpointID, hooked bool, hookedAddress tcpip.Address, hookedPort uint16) *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, linkEP tcpip.LinkEndpointID, hooked bool, hookedAddress tcpip.Address, hookedPort uint16) *tcpip.Error

CreateDisabledNamedNIC is a combination of CreateNamedNIC and CreateDisabledNIC.

func (*Stack) CreateNIC 

func (s *Stack) CreateNIC(id tcpip.NICID, linkEP tcpip.LinkEndpointID, hooked bool, hookedAddress tcpip.Address, hookedPort uint16) *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, linkEP tcpip.LinkEndpointID, hooked bool, hookedAddress tcpip.Address, hookedPort uint16) *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, linkEP tcpip.LinkEndpointID, hooked bool, hookedAddress tcpip.Address, hookedPort uint16) *tcpip.Error

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

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) 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.Address, tcpip.Subnet, *tcpip.Error)

GetMainNICAddress returns the first primary address (and the subnet that contains it) for the given NIC and protocol. Returns an arbitrary endpoint's address if no primary addresses exist. Returns an error if the NIC doesn't exist or has no endpoints.

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) 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) NICInfo 

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

NICInfo returns a map of NICIDs to their associated information.

func (*Stack) NICSubnets 

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

NICSubnets returns a map of NICIDs to their associated subnets.

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) NewRawEndpoint 

func (s *Stack) NewRawEndpoint(transport tcpip.TransportProtocolNumber, network tcpip.NetworkProtocolNumber, waiterQueue *waiter.Queue) (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) 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) RegisterTransportEndpoint 

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

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

RemoveSubnet removes the subnet range 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) SetForwarding 

func (s *Stack) SetForwarding(enable bool)

SetForwarding enables or disables the packet forwarding between NICs.

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, buffer.View, buffer.VectorisedView) 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) 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) 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)

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

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

	// 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
}

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. It also returns the network layer
	// header for the enpoint to inspect or pass up the stack.
	DeliverTransportPacket(r *Route, protocol tcpip.TransportProtocolNumber, netHeader buffer.View, vv buffer.VectorisedView)

	// DeliverTransportControlPacket delivers control packets to the
	// appropriate transport protocol endpoint.
	DeliverTransportControlPacket(local, remote tcpip.Address, net tcpip.NetworkProtocolNumber, trans tcpip.TransportProtocolNumber, typ ControlType, extra uint32, vv buffer.VectorisedView)
}

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 {
	// HandlePacket is called by the stack when new packets arrive to
	// this transport endpoint.
	HandlePacket(r *Route, id TransportEndpointID, vv buffer.VectorisedView)

	// HandleControlPacket is called by the stack when new control (e.g.,
	// ICMP) packets arrive to this transport endpoint.
	HandleControlPacket(id TransportEndpointID, typ ControlType, extra uint32, vv buffer.VectorisedView)
}

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 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(r *Route, id TransportEndpointID, vv buffer.VectorisedView) 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 TransportProtocolFactory 

type TransportProtocolFactory func() TransportProtocol

TransportProtocolFactory functions are used by the stack to instantiate transport protocols.

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