netstack

Documentation

Overview

Package netstack wires up gVisor's netstack into Tailscale.

Index

• type Impl
  • func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn, ...) (*Impl, error)
  • func (ns *Impl) Close() error
  • func (ns *Impl) DialContextTCP(ctx context.Context, ipp netip.AddrPort) (*gonet.TCPConn, error)
  • func (ns *Impl) DialContextUDP(ctx context.Context, ipp netip.AddrPort) (*gonet.UDPConn, error)
  • func (ns *Impl) ExpVar() expvar.Var
  • func (ns *Impl) ListenPacket(network, address string) (net.PacketConn, error)
  • func (ns *Impl) SetTransportProtocolOption(transport tcpip.TransportProtocolNumber, ...) tcpip.Error
  • func (ns *Impl) Start(lb *ipnlocal.LocalBackend) error
  • func (ns *Impl) UpdateNetstackIPs(nm *netmap.NetworkMap)

Types

type Impl

type Impl struct {
	// GetTCPHandlerForFlow conditionally handles an incoming TCP flow for the
	// provided (src/port, dst/port) 4-tuple.
	//
	// A nil value is equivalent to a func returning (nil, false).
	//
	// If func returns intercept=false, the default forwarding behavior (if
	// ProcessLocalIPs and/or ProcesssSubnetIPs) takes place.
	//
	// When intercept=true, the behavior depends on whether the returned handler
	// is non-nil: if nil, the connection is rejected. If non-nil, handler takes
	// over the TCP conn.
	GetTCPHandlerForFlow func(src, dst netip.AddrPort) (handler func(net.Conn), intercept bool)

	// GetUDPHandlerForFlow conditionally handles an incoming UDP flow for the
	// provided (src/port, dst/port) 4-tuple.
	//
	// A nil value is equivalent to a func returning (nil, false).
	//
	// If func returns intercept=false, the default forwarding behavior (if
	// ProcessLocalIPs and/or ProcesssSubnetIPs) takes place.
	//
	// When intercept=true, the behavior depends on whether the returned handler
	// is non-nil: if nil, the connection is rejected. If non-nil, handler takes
	// over the UDP flow.
	GetUDPHandlerForFlow func(src, dst netip.AddrPort) (handler func(nettype.ConnPacketConn), intercept bool)

	// ProcessLocalIPs is whether netstack should handle incoming
	// traffic directed at the Node.Addresses (local IPs).
	// It can only be set before calling Start.
	ProcessLocalIPs bool

	// ProcessSubnets is whether netstack should handle incoming
	// traffic destined to non-local IPs (i.e. whether it should
	// be a subnet router).
	// It can only be set before calling Start.
	ProcessSubnets bool
	// contains filtered or unexported fields
}

Impl contains the state for the netstack implementation, and implements wgengine.FakeImpl to act as a userspace network stack when Tailscale is running in fake mode.

func Create

func Create(logf logger.Logf, tundev *tstun.Wrapper, e wgengine.Engine, mc *magicsock.Conn, dialer *tsdial.Dialer, dns *dns.Manager, pm *proxymap.Mapper) (*Impl, error)

Create creates and populates a new Impl.

func (*Impl) Close

func (ns *Impl) Close() error

func (*Impl) DialContextTCP

func (ns *Impl) DialContextTCP(ctx context.Context, ipp netip.AddrPort) (*gonet.TCPConn, error)

func (*Impl) DialContextUDP

func (ns *Impl) DialContextUDP(ctx context.Context, ipp netip.AddrPort) (*gonet.UDPConn, error)

func (*Impl) ExpVar

func (ns *Impl) ExpVar() expvar.Var

ExpVar returns an expvar variable suitable for registering with expvar.Publish.

func (*Impl) ListenPacket

func (ns *Impl) ListenPacket(network, address string) (net.PacketConn, error)

ListenPacket listens for incoming packets for the given network and address. Address must be of the form "ip:port" or "[ip]:port".

As of 2024-05-18, only udp4 and udp6 are supported.

func (*Impl) SetTransportProtocolOption

func (ns *Impl) SetTransportProtocolOption(transport tcpip.TransportProtocolNumber, option tcpip.SettableTransportProtocolOption) tcpip.Error

SetTransportProtocolOption forwards to the underlying stack.Stack.SetTransportProtocolOption. Callers are responsible for ensuring that the options are valid, compatible and appropriate for their use case. Compatibility may change at any version.

func (*Impl) Start

func (ns *Impl) Start(lb *ipnlocal.LocalBackend) error

Start sets up all the handlers so netstack can start working. Implements wgengine.FakeImpl.

func (*Impl) UpdateNetstackIPs

func (ns *Impl) UpdateNetstackIPs(nm *netmap.NetworkMap)

UpdateNetstackIPs updates the set of local IPs that netstack should handle from nm.

TODO(bradfitz): don't pass the whole netmap here; just pass the two address slice views.