netutil

Documentation

Overview

Utilities for working with networks and network accessories.

Utilities for working with networks and network accessories.

Index

• Variables
• func DefaultGateway() (net.IP, error)
• func EphemeralPort() (int, error)
• func ExpandPort(address string) string
• func FQDN() string
• func HasRoutableIP(network string, ifi *net.Interface) (net.IP, bool)
• func IsMulticastCapable(network string, ifi *net.Interface) (net.IP, bool)
• func IsRoutableIP(network string, ip net.IP) net.IP
• func OnePingOnly(dest net.IP, source *IPAddress, timeout time.Duration) error
• func RoutedInterface(network string, flags net.Flags) *net.Interface
• func WaitForGatewayPing(totaltime time.Duration) error
• func WaitForGatewayPing6(totaltime time.Duration) error
• func WaitForOpen(network string, address string, totaltime time.Duration, ...) error
• func WaitForPing(addr interface{}, totaltime time.Duration) error
• func ZeroconfDiscover(options *ZeroconfOptions, fn ServiceFunc) error
• func ZeroconfRegister(svc *Service) (string, error)
• func ZeroconfUnregister(id string)
• func ZeroconfUnregisterAll()
• type IPAddress
  • func DefaultAddress() *IPAddress
  • func DefaultAddress6() *IPAddress
  • func GetRoutableAddresses(gateway net.IP, iface *net.Interface) ([]*IPAddress, error)
  • func RoutableAddresses() ([]*IPAddress, error)
• type Service
  • func (self *Service) String() string
• type ServiceFunc
• type ZeroconfOptions

Variables

var DefaultWaitForOpenConnectionTimeout = 5 * time.Second

var WaitForOpenCheckInterval = time.Second

var WaitForPingCheckInterval = time.Second

var WaitForPingReply = 5 * time.Second

Functions

func DefaultGateway

func DefaultGateway() (net.IP, error)

Retrieves the default gateway interface.

func EphemeralPort

func EphemeralPort() (int, error)

Retrieve an open ephemeral port.

func ExpandPort

func ExpandPort(address string) string

Takes an address in the form of "host:port", looks for port zero (e.g: ":0"), and gets an ephemeral local port and returns that address (e.g.: ":41327").

func FQDN

func FQDN() string

Return the current machine's Fully-qualified domain name,

func HasRoutableIP

func HasRoutableIP(network string, ifi *net.Interface) (net.IP, bool)

Returns the first routable address on the given interface.

func IsMulticastCapable

func IsMulticastCapable(network string, ifi *net.Interface) (net.IP, bool)

IsMulticastCapable reports whether ifi is an IP multicast-capable network interface. Network must be "ip", "ip4" or "ip6".

func IsRoutableIP

func IsRoutableIP(network string, ip net.IP) net.IP

Returns true when the given address is unicast routable beyond the current machine.

func OnePingOnly

func OnePingOnly(dest net.IP, source *IPAddress, timeout time.Duration) error

Send a single ICMP ECHO request packet to the given address on the given interface and wait for up to timeout for a reply.

func RoutedInterface

func RoutedInterface(network string, flags net.Flags) *net.Interface

RoutedInterface returns a network interface that can route IP traffic and satisfies flags. It returns nil when an appropriate network interface is not found. Network must be "ip", "ip4" or "ip6".

func WaitForGatewayPing

func WaitForGatewayPing(totaltime time.Duration) error

Like WaitForPing, but will identify the default gateway and ping that address.

func WaitForGatewayPing6

func WaitForGatewayPing6(totaltime time.Duration) error

Like WaitForGatewayPing, but specifically pings an IPv6 gateway

func WaitForOpen

func WaitForOpen(network string, address string, totaltime time.Duration, timeouts ...time.Duration) error

Periodically attempts to open a TCP socket to the given address, up to totaltime. Returns nil if the socket was opened successfully (which will then immediately be closed), or an error if the function timed out. The check interval can be configured using the WaitForOpenCheckInterval package variable.

func WaitForPing

func WaitForPing(addr interface{}, totaltime time.Duration) error

Periodically attempts to send an ICMP ECHO request (a "ping") to the given IP address, up to totaltime. Returns nil if an ECHO reply was received, or an error if the function timed out. The check interval can be configured using the WaitForPingCheckInterval package variable.

func ZeroconfDiscover

func ZeroconfDiscover(options *ZeroconfOptions, fn ServiceFunc) error

Perform Multicast DNS discovery on the local network, calling the fn callback for each discovered service.

func ZeroconfRegister

func ZeroconfRegister(svc *Service) (string, error)

Register the given service in Multicast DNS. Returns an ID that can be used to unregister the service later.

func ZeroconfUnregister

func ZeroconfUnregister(id string)

Unregister a previously-registered service.

func ZeroconfUnregisterAll

func ZeroconfUnregisterAll()

Unregister all Multicast DNS services.

Types

type IPAddress

type IPAddress struct {
	IP        net.IP
	Mask      net.IPMask
	Interface net.Interface
	Gateway   net.IP
}

func DefaultAddress

func DefaultAddress() *IPAddress

Retrieves the first routable IP address on any interface that falls inside of the system's default gateway network. Will return nil if no IP could be found.

func DefaultAddress6

func DefaultAddress6() *IPAddress

Like DefaultAddress, but specifically filters on IPv6 addresses. If no routable IPv6 address is found, returns nil.

func GetRoutableAddresses

func GetRoutableAddresses(gateway net.IP, iface *net.Interface) ([]*IPAddress, error)

Returns all addresses on the given interface that can route to the given gateway. If gateway is nil, the default gateway will be attempted.

func RoutableAddresses

func RoutableAddresses() ([]*IPAddress, error)

Return a list of routable IP addresses, along with their associated gateways and interfaces.

type Service

type Service struct {
	Hostname   string          `json:"hostname"`
	Instance   string          `json:"instance"`
	Service    string          `json:"service"`
	Domain     string          `json:"domain"`
	Port       int             `json:"port"`
	Text       []string        `json:"txt"`
	Address    string          `json:"address"`
	Addresses  []net.IP        `json:"addresses,omitempty"`
	Interfaces []net.Interface `json:"interfaces,omitempty"`
}

func (*Service) String

func (self *Service) String() string

type ServiceFunc

type ServiceFunc func(*Service) bool

type ZeroconfOptions

type ZeroconfOptions struct {
	Context       context.Context
	Limit         int
	Timeout       time.Duration `default:"30s"`
	Service       string        `default:"_http._tcp"`
	Domain        string        `default:".local"`
	CheckInterval time.Duration `default:"100ms"`
	MatchInstance string
	MatchPort     string
	MatchHostname string
	MatchAddress  string
}