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) 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) 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.