netutil

Documentation

Overview

Package netutil contains extensions to the net package.

Index

• func AddrAddr(addr net.Addr) netip.Addr
• func AddrIsLAN(ip netip.Addr) bool
• func AddrIsSpecialNetwork(ip netip.Addr) bool
• func CheckRelayAddr(sender, addr netip.Addr) error
• func CheckRelayIP(sender, addr net.IP) error
• func IPToAddr(ip net.IP) netip.Addr
• func IsLAN(ip net.IP) bool
• func IsSpecialNetwork(ip net.IP) bool
• func IsTemporaryError(err error) bool
• func IsTimeout(err error) bool
• func RandomAddr(rng *rand.Rand, ipv4 bool) netip.Addr
• func SameNet(bits uint, ip, other net.IP) bool
• type DistinctNetSet
  • func (s *DistinctNetSet) Add(ip net.IP) bool
  • func (s *DistinctNetSet) AddAddr(ip netip.Addr) bool
  • func (s DistinctNetSet) Contains(ip net.IP) bool
  • func (s DistinctNetSet) ContainsAddr(ip netip.Addr) bool
  • func (s DistinctNetSet) Len() int
  • func (s *DistinctNetSet) Remove(ip net.IP)
  • func (s *DistinctNetSet) RemoveAddr(ip netip.Addr)
  • func (s DistinctNetSet) String() string
• type IPTracker
  • func NewIPTracker(window, contactWindow time.Duration, minStatements int) *IPTracker
  • func (it *IPTracker) AddContact(host netip.Addr)
  • func (it *IPTracker) AddStatement(host netip.Addr, endpoint netip.AddrPort)
  • func (it *IPTracker) PredictEndpoint() netip.AddrPort
  • func (it *IPTracker) PredictFullConeNAT() bool
• type Netlist
  • func ParseNetlist(s string) (*Netlist, error)
  • func (l *Netlist) Add(cidr string)
  • func (l *Netlist) Contains(ip net.IP) bool
  • func (l *Netlist) ContainsAddr(ip netip.Addr) bool
  • func (l Netlist) MarshalTOML() interface{}
  • func (l *Netlist) UnmarshalTOML(fn func(interface{}) error) error

Examples

• SameNet

Functions

func AddrAddr

func AddrAddr(addr net.Addr) netip.Addr

AddrAddr gets the IP address contained in addr. The result will be invalid if the address type is unsupported.

func AddrIsLAN

func AddrIsLAN(ip netip.Addr) bool

AddrIsLAN reports whether an IP is a local network address.

func AddrIsSpecialNetwork

func AddrIsSpecialNetwork(ip netip.Addr) bool

AddrIsSpecialNetwork reports whether an IP is located in a special-use network range This includes broadcast, multicast and documentation addresses.

func CheckRelayAddr

func CheckRelayAddr(sender, addr netip.Addr) error

CheckRelayAddr reports whether an IP relayed from the given sender IP is a valid connection target.

There are four rules:

• Special network addresses are never valid.
• Loopback addresses are OK if relayed by a loopback host.
• LAN addresses are OK if relayed by a LAN host.
• All other addresses are always acceptable.

func CheckRelayIP

func CheckRelayIP(sender, addr net.IP) error

CheckRelayIP reports whether an IP relayed from the given sender IP is a valid connection target.

There are four rules:

• Special network addresses are never valid.
• Loopback addresses are OK if relayed by a loopback host.
• LAN addresses are OK if relayed by a LAN host.
• All other addresses are always acceptable.

func IPToAddr

func IPToAddr(ip net.IP) netip.Addr

IPToAddr converts net.IP to netip.Addr. Note that unlike netip.AddrFromSlice, this function will always ensure that the resulting Addr is IPv4 when the input is.

func IsLAN

func IsLAN(ip net.IP) bool

IsLAN reports whether an IP is a local network address.

func IsSpecialNetwork

func IsSpecialNetwork(ip net.IP) bool

IsSpecialNetwork reports whether an IP is located in a special-use network range This includes broadcast, multicast and documentation addresses.

func IsTemporaryError

func IsTemporaryError(err error) bool

IsTemporaryError checks whether the given error should be considered temporary.

func IsTimeout

func IsTimeout(err error) bool

IsTimeout checks whether the given error is a timeout.

func RandomAddr

func RandomAddr(rng *rand.Rand, ipv4 bool) netip.Addr

RandomAddr creates a random IP address.

func SameNet

func SameNet(bits uint, ip, other net.IP) bool

SameNet reports whether two IP addresses have an equal prefix of the given bit length.

Example

// This returns true because the IPs are in the same /24 network:
fmt.Println(SameNet(24, net.IP{127, 0, 0, 1}, net.IP{127, 0, 0, 3}))
// This call returns false:
fmt.Println(SameNet(24, net.IP{127, 3, 0, 1}, net.IP{127, 5, 0, 3}))

Output:

true
false

Types

type DistinctNetSet

type DistinctNetSet struct {
	Subnet uint // number of common prefix bits
	Limit  uint // maximum number of IPs in each subnet
	// contains filtered or unexported fields
}

DistinctNetSet tracks IPs, ensuring that at most N of them fall into the same network range.

func (*DistinctNetSet) Add

func (s *DistinctNetSet) Add(ip net.IP) bool

Add adds an IP address to the set. It returns false (and doesn't add the IP) if the number of existing IPs in the defined range exceeds the limit.

func (*DistinctNetSet) AddAddr

func (s *DistinctNetSet) AddAddr(ip netip.Addr) bool

AddAddr adds an IP address to the set. It returns false (and doesn't add the IP) if the number of existing IPs in the defined range exceeds the limit.

func (DistinctNetSet) Contains

func (s DistinctNetSet) Contains(ip net.IP) bool

Contains reports whether the given IP is contained in the set.

func (DistinctNetSet) ContainsAddr

func (s DistinctNetSet) ContainsAddr(ip netip.Addr) bool

ContainsAddr reports whether the given IP is contained in the set.

func (DistinctNetSet) Len

func (s DistinctNetSet) Len() int

Len returns the number of tracked IPs.

func (*DistinctNetSet) Remove

func (s *DistinctNetSet) Remove(ip net.IP)

Remove removes an IP from the set.

func (*DistinctNetSet) RemoveAddr

func (s *DistinctNetSet) RemoveAddr(ip netip.Addr)

RemoveAddr removes an IP from the set.

func (DistinctNetSet) String

func (s DistinctNetSet) String() string

String implements fmt.Stringer

type IPTracker

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

IPTracker predicts the external endpoint, i.e. IP address and port, of the local host based on statements made by other hosts.

func NewIPTracker

func NewIPTracker(window, contactWindow time.Duration, minStatements int) *IPTracker

NewIPTracker creates an IP tracker.

The window parameters configure the amount of past network events which are kept. The minStatements parameter enforces a minimum number of statements which must be recorded before any prediction is made. Higher values for these parameters decrease 'flapping' of predictions as network conditions change. Window duration values should typically be in the range of minutes.

func (*IPTracker) AddContact

func (it *IPTracker) AddContact(host netip.Addr)

AddContact records that a packet containing our endpoint information has been sent to a certain host.

func (*IPTracker) AddStatement

func (it *IPTracker) AddStatement(host netip.Addr, endpoint netip.AddrPort)

AddStatement records that a certain host thinks our external endpoint is the one given.

func (*IPTracker) PredictEndpoint

func (it *IPTracker) PredictEndpoint() netip.AddrPort

PredictEndpoint returns the current prediction of the external endpoint.

func (*IPTracker) PredictFullConeNAT

func (it *IPTracker) PredictFullConeNAT() bool

PredictFullConeNAT checks whether the local host is behind full cone NAT. It predicts by checking whether any statement has been received from a node we didn't contact before the statement was made.

type Netlist

type Netlist []netip.Prefix

Netlist is a list of IP networks.

func ParseNetlist

func ParseNetlist(s string) (*Netlist, error)

ParseNetlist parses a comma-separated list of CIDR masks. Whitespace and extra commas are ignored.

func (*Netlist) Add

func (l *Netlist) Add(cidr string)

Add parses a CIDR mask and appends it to the list. It panics for invalid masks and is intended to be used for setting up static lists.

func (*Netlist) Contains

func (l *Netlist) Contains(ip net.IP) bool

Contains reports whether the given IP is contained in the list.

func (*Netlist) ContainsAddr

func (l *Netlist) ContainsAddr(ip netip.Addr) bool

ContainsAddr reports whether the given IP is contained in the list.

func (Netlist) MarshalTOML

func (l Netlist) MarshalTOML() interface{}

MarshalTOML implements toml.MarshalerRec.

func (*Netlist) UnmarshalTOML

func (l *Netlist) UnmarshalTOML(fn func(interface{}) error) error

UnmarshalTOML implements toml.UnmarshalerRec.