netmon

package
v1.69.0-pre Latest Latest
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 Go to latest Published: Jun 12, 2024 License: BSD-3-Clause Imports: 32 Imported by: 60

Documentation

Overview

Package monitor provides facilities for monitoring network interface and route changes. It primarily exists to know when portable devices move between different networks.

Package interfaces contains helpers for looking up system network interfaces.

Index

Constants

This section is empty.

Variables

View Source 
var LoginEndpointForProxyDetermination = "https://controlplane.tailscale.com/"

LoginEndpointForProxyDetermination is the URL used for testing which HTTP proxy the system should use.

Functions

func DefaultRouteInterface added in v1.66.0 

func DefaultRouteInterface() (string, error)

DefaultRouteInterface is like DefaultRoute but only returns the interface name.

func ForeachInterface added in v1.66.0 

func ForeachInterface(fn func(Interface, []netip.Prefix)) error

ForeachInterface is a wrapper for GetList, then List.ForeachInterface.

func ForeachInterfaceAddress added in v1.66.0 

func ForeachInterfaceAddress(fn func(Interface, netip.Prefix)) error

ForeachInterfaceAddress is a wrapper for GetList, then List.ForeachInterfaceAddress.

func HTTPOfListener added in v1.66.0 

func HTTPOfListener(ln net.Listener) string

HTTPOfListener returns the HTTP address to ln. If the listener is listening on the unspecified address, it it tries to find a reasonable interface address on the machine to use.

func HasCGNATInterface added in v1.66.0 

func HasCGNATInterface() (bool, error)

HasCGNATInterface reports whether there are any non-Tailscale interfaces that use a CGNAT IP range.

func InterfaceDebugExtras added in v1.66.0 

func InterfaceDebugExtras(ifIndex int) (string, error)

InterfaceDebugExtras returns extra debugging information about an interface if any (an empty string will be returned if there are no additional details). Formatting is platform-dependent and should not be parsed.

func LikelyHomeRouterIP added in v1.66.0 

func LikelyHomeRouterIP() (gateway, myIP netip.Addr, ok bool)

LikelyHomeRouterIP returns the likely IP of the residential router, which will always be an IPv4 private address, if found. In addition, it returns the IP address of the current machine on the LAN using that gateway. This is used as the destination for UPnP, NAT-PMP, PCP, etc queries.

func LocalAddresses added in v1.66.0 

func LocalAddresses() (regular, loopback []netip.Addr, err error)

LocalAddresses returns the machine's IP addresses, separated by whether they're loopback addresses. If there are no regular addresses it will return any IPv4 linklocal or IPv6 unique local addresses because we know of environments where these are used with NAT to provide connectivity.

func RegisterInterfaceGetter added in v1.66.0 

func RegisterInterfaceGetter(getInterfaces func() ([]Interface, error))

RegisterInterfaceGetter sets the function that's used to query the system network interfaces.

Types

type ChangeDelta added in v1.50.0 

type ChangeDelta struct {
	// Monitor is the network monitor that sent this delta.
	Monitor *Monitor

	// Old is the old interface state, if known.
	// It's nil if the old state is unknown.
	// Do not mutate it.
	Old *State

	// New is the new network state.
	// It is always non-nil.
	// Do not mutate it.
	New *State

	// Major is our legacy boolean of whether the network changed in some major
	// way.
	//
	// Deprecated: do not remove. As of 2023-08-23 we're in a renewed effort to
	// remove it and ask specific qustions of ChangeDelta instead. Look at Old
	// and New (or add methods to ChangeDelta) instead of using Major.
	Major bool

	// TimeJumped is whether there was a big jump in wall time since the last
	// time we checked. This is a hint that a mobile sleeping device might have
	// come out of sleep.
	TimeJumped bool
}

ChangeDelta describes the difference between two network states.

type ChangeFunc 

type ChangeFunc func(*ChangeDelta)

ChangeFunc is a callback function registered with Monitor that's called when the network changed.

type DefaultRouteDetails added in v1.66.0 

type DefaultRouteDetails struct {
	// InterfaceName is the interface name. It must always be populated.
	// It's like "eth0" (Linux), "Ethernet 2" (Windows), "en0" (macOS).
	InterfaceName string

	// InterfaceDesc is populated on Windows at least. It's a
	// longer description, like "Red Hat VirtIO Ethernet Adapter".
	InterfaceDesc string

	// InterfaceIndex is like net.Interface.Index.
	// Zero means not populated.
	InterfaceIndex int
}

DefaultRouteDetails are the details about a default route returned by DefaultRoute.

func DefaultRoute added in v1.66.0 

func DefaultRoute() (DefaultRouteDetails, error)

DefaultRoute returns details of the network interface that owns the default route, not including any tailscale interfaces.

type Interface added in v1.66.0 

type Interface struct {
	*net.Interface
	AltAddrs []net.Addr // if non-nil, returned by Addrs
	Desc     string     // extra description (used on Windows)
}

Interface is a wrapper around Go's net.Interface with some extra methods.

func (Interface) Addrs added in v1.66.0 

func (i Interface) Addrs() ([]net.Addr, error)

func (Interface) Equal added in v1.66.0 

func (a Interface) Equal(b Interface) bool

func (Interface) IsLoopback added in v1.66.0 

func (i Interface) IsLoopback() bool

func (Interface) IsUp added in v1.66.0 

func (i Interface) IsUp() bool

type InterfaceList added in v1.66.0 

type InterfaceList []Interface

InterfaceList is a list of interfaces on the machine.

func GetInterfaceList added in v1.66.0 

func GetInterfaceList() (InterfaceList, error)

GetInterfaceList returns the list of interfaces on the machine.

func (InterfaceList) ForeachInterface added in v1.66.0 

func (ifaces InterfaceList) ForeachInterface(fn func(Interface, []netip.Prefix)) error

ForeachInterface calls fn for each interface in ifaces, with all its addresses. The IPPrefix's IP is the IP address assigned to the interface, and Bits are the subnet mask.

func (InterfaceList) ForeachInterfaceAddress added in v1.66.0 

func (ifaces InterfaceList) ForeachInterfaceAddress(fn func(Interface, netip.Prefix)) error

ForeachInterfaceAddress calls fn for each interface in ifaces, with all its addresses. The IPPrefix's IP is the IP address assigned to the interface, and Bits are the subnet mask.

type Monitor 

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

Monitor represents a monitoring instance.

func New 

func New(logf logger.Logf) (*Monitor, error)

New instantiates and starts a monitoring instance. The returned monitor is inactive until it's started by the Start method. Use RegisterChangeCallback to get notified of network changes.

func NewStatic added in v1.66.0 

func NewStatic() *Monitor

NewStatic returns a Monitor that's a one-time snapshot of the network state but doesn't actually monitor for changes. It should only be used in tests and situations like cleanups or short-lived CLI programs.

func (*Monitor) Close 

func (m *Monitor) Close() error

Close closes the monitor.

func (*Monitor) GatewayAndSelfIP 

func (m *Monitor) GatewayAndSelfIP() (gw, myIP netip.Addr, ok bool)

GatewayAndSelfIP returns the current network's default gateway, and the machine's default IP for that gateway.

It's the same as interfaces.LikelyHomeRouterIP, but it caches the result until the monitor detects a network change.

func (*Monitor) InjectEvent 

func (m *Monitor) InjectEvent()

InjectEvent forces the monitor to pretend there was a network change and re-check the state of the network. Any registered ChangeFunc callbacks will be called within the event coalescing period (under a fraction of a second).

func (*Monitor) InterfaceState 

func (m *Monitor) InterfaceState() *State

InterfaceState returns the latest snapshot of the machine's network interfaces.

The returned value is owned by Mon; it must not be modified.

func (*Monitor) IsMajorChangeFrom added in v1.50.0 

func (m *Monitor) IsMajorChangeFrom(s1, s2 *State) bool

IsMajorChangeFrom reports whether the transition from s1 to s2 is a "major" change, where major roughly means it's worth tearing down a bunch of connections and rebinding.

TODO(bradiftz): tigten this definition.

func (*Monitor) Poll added in v1.50.0 

func (m *Monitor) Poll()

Poll forces the monitor to pretend there was a network change and re-check the state of the network.

This is like InjectEvent but only fires ChangeFunc callbacks if the network state differed at all.

func (*Monitor) RegisterChangeCallback 

func (m *Monitor) RegisterChangeCallback(callback ChangeFunc) (unregister func())

RegisterChangeCallback adds callback to the set of parties to be notified (in their own goroutine) when the network state changes. To remove this callback, call unregister (or close the monitor).

func (*Monitor) RegisterRuleDeleteCallback 

func (m *Monitor) RegisterRuleDeleteCallback(callback RuleDeleteCallback) (unregister func())

RegisterRuleDeleteCallback adds callback to the set of parties to be notified (in their own goroutine) when a Linux ip rule is deleted. To remove this callback, call unregister (or close the monitor).

func (*Monitor) SetTailscaleInterfaceName added in v1.50.0 

func (m *Monitor) SetTailscaleInterfaceName(ifName string)

SetTailscaleInterfaceName sets the name of the Tailscale interface. For example, "tailscale0", "tun0", "utun3", etc.

This must be called only early in tailscaled startup before the monitor is used.

func (*Monitor) Start 

func (m *Monitor) Start()

Start starts the monitor. A monitor can only be started & closed once.

type RuleDeleteCallback 

type RuleDeleteCallback func(table uint8, priority uint32)

RuleDeleteCallback is a callback when a Linux IP policy routing rule is deleted. The table is the table number (52, 253, 354) and priority is the priority order number (for Tailscale rules currently: 5210, 5230, 5250, 5270)

type State added in v1.66.0 

type State struct {
	// InterfaceIPs maps from an interface name to the IP addresses
	// configured on that interface. Each address is represented as an
	// IPPrefix, where the IP is the interface IP address and Bits is
	// the subnet mask.
	InterfaceIPs map[string][]netip.Prefix
	Interface    map[string]Interface

	// HaveV6 is whether this machine has an IPv6 Global or Unique Local Address
	// which might provide connectivity on a non-Tailscale interface that's up.
	HaveV6 bool

	// HaveV4 is whether the machine has some non-localhost,
	// non-link-local IPv4 address on a non-Tailscale interface that's up.
	HaveV4 bool

	// IsExpensive is whether the current network interface is
	// considered "expensive", which currently means LTE/etc
	// instead of Wifi. This field is not populated by GetState.
	IsExpensive bool

	// DefaultRouteInterface is the interface name for the
	// machine's default route.
	//
	// It is not yet populated on all OSes.
	//
	// When non-empty, its value is the map key into Interface and
	// InterfaceIPs.
	DefaultRouteInterface string

	// HTTPProxy is the HTTP proxy to use, if any.
	HTTPProxy string

	// PAC is the URL to the Proxy Autoconfig URL, if applicable.
	PAC string
}

State is intended to store the state of the machine's network interfaces, routing table, and other network configuration. For now it's pretty basic.

func GetState deprecated added in v1.66.0 

func GetState() (*State, error)

GetState returns the state of all the current machine's network interfaces.

It does not set the returned State.IsExpensive. The caller can populate that.

Deprecated: use netmon.Monitor.InterfaceState instead.

func (*State) AnyInterfaceUp added in v1.66.0 

func (s *State) AnyInterfaceUp() bool

AnyInterfaceUp reports whether any interface seems like it has Internet access.

func (*State) Equal added in v1.66.0 

func (s *State) Equal(s2 *State) bool

Equal reports whether s and s2 are exactly equal.

func (*State) HasIP added in v1.66.0 

func (s *State) HasIP(ip netip.Addr) bool

HasIP reports whether any interface has the provided IP address.

func (*State) HasPAC added in v1.66.0 

func (s *State) HasPAC() bool

func (*State) String added in v1.66.0 

func (s *State) String() string

Source Files

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