subnet

Documentation

Overview

Package subnet contains functions for finding available subnets

Index

• func CoveringCIDRs(ips []net.IP) []*net.IPNet
• func Covers(a, b *net.IPNet) bool
• func Equal(a, b *net.IPNet) bool
• func IsHalfOfDefault(n *net.IPNet) bool
• func IsZeroMask(n *net.IPNet) bool
• func Overlaps(a, b *net.IPNet) bool
• func Partition(subnets []*net.IPNet, filter func(int, *net.IPNet) bool) (matched, notMatched []*net.IPNet)
• func RandomIPv4Subnet(mask net.IPMask, avoid []*net.IPNet) (*net.IPNet, error)
• func Unique(subnets []*net.IPNet) []*net.IPNet
• type Bitfield256
  • func (b *Bitfield256) ClearBit(bv byte)
  • func (b *Bitfield256) Equals(other *Bitfield256) bool
  • func (b *Bitfield256) GetBit(bv byte) bool
  • func (b *Bitfield256) Mask() (ones int, value byte)
  • func (b *Bitfield256) OnesCount() (l int)
  • func (b *Bitfield256) SetBit(bv byte)
  • func (b *Bitfield256) String() string
  • func (b *Bitfield256) ToSlice() []byte
• type Set
  • func NewSet(subnets []*net.IPNet) Set
  • func (s Set) Add(subnet *net.IPNet) bool
  • func (s Set) AppendSortedTo(subnets []*net.IPNet) []*net.IPNet
  • func (s Set) Clone() Set
  • func (s Set) Delete(subnet *net.IPNet) bool
  • func (s Set) Equals(o Set) bool
  • func (s Set) String() string

Functions

func CoveringCIDRs

func CoveringCIDRs(ips []net.IP) []*net.IPNet

CoveringCIDRs returns the ip networks needed to cover the given IPs with as big mask as possible for each subnet. The analysis starts by finding all subnets using a 16-bit mask for IPv4 and a 64 bit mask for IPv6 addresses. Once the subnets are established, the mask for each one will be increased to the maximum value that still masks all IPs that it was created for.

Note: A similar method exists in Telepresence 1, but this method was not compared to it when written.

func Covers

func Covers(a, b *net.IPNet) bool

Covers answers the question if network range a contains the full network range b.

func Equal

func Equal(a, b *net.IPNet) bool

Equal returns true if a and b have equal IP and masks.

func IsHalfOfDefault

func IsHalfOfDefault(n *net.IPNet) bool

IsHalfOfDefault route returns true if the given subnet covers half the address space with a /1 mask.

func IsZeroMask

func IsZeroMask(n *net.IPNet) bool

func Overlaps

func Overlaps(a, b *net.IPNet) bool

Overlaps answers the question if there is an overlap between network range a and b.

func Partition

func Partition(subnets []*net.IPNet, filter func(int, *net.IPNet) bool) (matched, notMatched []*net.IPNet)

Partition returns two slices, the first containing the subnets for which the filter evaluates to true, the second containing the rest.

func RandomIPv4Subnet

func RandomIPv4Subnet(mask net.IPMask, avoid []*net.IPNet) (*net.IPNet, error)

RandomIPv4Subnet finds a random free subnet using the given mask. A subnet is considered free if it doesn't overlap with any of the subnets returned by the net.InterfaceAddrs function or with any of the subnets provided in the avoid parameter. The returned subnet will be a private IPv4 subnet in either class C, B, or A range, and the search for a free subnet uses that order. See https://en.wikipedia.org/wiki/Private_network for more info about private subnets.

func Unique

func Unique(subnets []*net.IPNet) []*net.IPNet

Unique will drop any subnet that is covered by another subnet from the given slice and return the resulting slice. This function will alter the given slice.

Types

type Bitfield256

type Bitfield256 [4]uint64

Bitfield256 represents 0 - 255 unique bytes.

func (*Bitfield256) ClearBit

func (b *Bitfield256) ClearBit(bv byte)

ClearBit clears the 1<<bv bit of the bitfield to 0.

func (*Bitfield256) Equals

func (b *Bitfield256) Equals(other *Bitfield256) bool

Equals returns true if this Bitfield256 equals the argument.

func (*Bitfield256) GetBit

func (b *Bitfield256) GetBit(bv byte) bool

GetBit returns the value of the 1<<bv bit of the bitfield (0 is false, 1 is true).

func (*Bitfield256) Mask

func (b *Bitfield256) Mask() (ones int, value byte)

Mask returns how many bits, from left to right, that have the same value for all bytes represented by this Bitfield256 and a byte containing the value of those bits.

func (*Bitfield256) OnesCount

func (b *Bitfield256) OnesCount() (l int)

OnesCount returns the number of 1 bits in the bitfield.

func (*Bitfield256) SetBit

func (b *Bitfield256) SetBit(bv byte)

SetBit sets the 1<<bv bit of the bitfield to 1.

func (*Bitfield256) String

func (b *Bitfield256) String() string

String prints the hexadecimal representation of the bits.

func (*Bitfield256) ToSlice

func (b *Bitfield256) ToSlice() []byte

ToSlice returns an ordered slice of all bytes in this Bitfield256.

type Set

type Set map[setKey]struct{}

Set represents a unique unordered set of subnets.

func NewSet

func NewSet(subnets []*net.IPNet) Set

func (Set) Add

func (s Set) Add(subnet *net.IPNet) bool

Add adds a subnet to this set unless it doesn't already exist. Returns true if the subnet was added, false otherwise.

func (Set) AppendSortedTo

func (s Set) AppendSortedTo(subnets []*net.IPNet) []*net.IPNet

AppendSortedTo appends the sorted subnets of this set to the given slice and returns the resulting slice.

func (Set) Clone

func (s Set) Clone() Set

Clone returns a copy of this Set.

func (Set) Delete

func (s Set) Delete(subnet *net.IPNet) bool

Delete deletes a subnet equal to the given subnet. Returns true if the subnet was deleted, false otherwise.

func (Set) Equals

func (s Set) Equals(o Set) bool

Equals returns true if the two sets have the same content.

func (Set) String

func (s Set) String() string