extnetip

README

package extnetip

Package extnetip is an extension to net/netip with a few missing but important auxiliary functions for converting IP-prefixes to IP-ranges and vice versa.

With these extensions to net/netip, third-party IP-range libraries become easily possible.

API

import "github.com/gaissmai/extnetip"

func Range(p netip.Prefix) (first, last netip.Addr)
func Prefix(first, last netip.Addr) (prefix netip.Prefix, ok bool)
func All(first, last netip.Addr) iter.Seq[netip.Prefix]

// Deprecated: func Prefixes(first, last netip.Addr) []netip.Prefix
// Deprecated: func PrefixesAppend(dst []netip.Prefix, first, last netip.Addr) []netip.Prefix

Future

Hopefully some day these needed helper functions are added to netip by the stdlib maintainers.

Documentation

Overview

Package extnetip is an extension to net/netip with a few missing but important auxiliary functions for converting IP-prefixes to IP-ranges and vice versa.

The functions are effectively performed in uint128 space, no conversions from/to bytes are performed.

With these extensions to net/netip, third-party IP-range libraries become easily possible.

Index

• func All(first, last netip.Addr) iter.Seq[netip.Prefix]
• func Prefix(first, last netip.Addr) (prefix netip.Prefix, ok bool)
• func Prefixes(first, last netip.Addr) []netip.Prefix
• func PrefixesAppend(dst []netip.Prefix, first, last netip.Addr) []netip.Prefix
• func Range(p netip.Prefix) (first, last netip.Addr)

Examples

• All
• Prefix
• Range

Functions

func All

func All(first, last netip.Addr) iter.Seq[netip.Prefix]

All returns an iterator over the set of prefixes that covers the range from [first, last].

If first or last are not valid, in the wrong order or not of the same version, the set is empty.

Example

package main

import (
	"fmt"
	"net/netip"

	"github.com/gaissmai/extnetip"
)

func main() {
	first := netip.MustParseAddr("10.1.0.0")
	last := netip.MustParseAddr("10.1.13.233")

	fmt.Println("Prefixes:")
	for pfx := range extnetip.All(first, last) {
		fmt.Println(pfx)
	}

}

Output:

Prefixes:
10.1.0.0/21
10.1.8.0/22
10.1.12.0/24
10.1.13.0/25
10.1.13.128/26
10.1.13.192/27
10.1.13.224/29
10.1.13.232/31

func Prefix

func Prefix(first, last netip.Addr) (prefix netip.Prefix, ok bool)

Prefix returns the netip.Prefix from first to last and ok=true, if it can be presented exactly as such.

If first or last are not valid, in the wrong order or not exactly equal to one prefix, ok is false.

Example

package main

import (
	"fmt"
	"net/netip"

	"github.com/gaissmai/extnetip"
)

func main() {
	first := netip.MustParseAddr("fe80::")
	last := netip.MustParseAddr("fe80::7")

	pfx, ok := extnetip.Prefix(first, last)

	fmt.Println("OK:    ", ok)
	fmt.Println("Prefix:", pfx)

	fmt.Println()

	first = netip.MustParseAddr("10.0.0.1")
	last = netip.MustParseAddr("10.0.0.19")

	pfx, ok = extnetip.Prefix(first, last)

	fmt.Println("OK:    ", ok)
	fmt.Println("Prefix:", pfx)

}

Output:

OK:     true
Prefix: fe80::/125

OK:     false
Prefix: invalid Prefix

func Prefixes

func Prefixes(first, last netip.Addr) []netip.Prefix

Prefixes returns the set of netip.Prefix entries that covers the IP range from first to last.

If first or last are invalid, in the wrong order, or if they're of different address families, then Prefixes returns nil.

Deprecated: Prefixes is deprecated. Use the iterator version All instead.

func PrefixesAppend

func PrefixesAppend(dst []netip.Prefix, first, last netip.Addr) []netip.Prefix

PrefixesAppend is an append version of Prefixes. It appends the netip.Prefix entries to dst that covers the IP range from first to last.

Deprecated: PrefixesAppend is deprecated. Use the iterator version All instead.

func Range

func Range(p netip.Prefix) (first, last netip.Addr)

Range returns the inclusive range of IP addresses [first, last] that p covers.

If p is invalid, Range returns the zero values.

Example

package main

import (
	"fmt"
	"net/netip"

	"github.com/gaissmai/extnetip"
)

func main() {
	pfx := netip.MustParsePrefix("fe80::/10")
	first, last := extnetip.Range(pfx)

	fmt.Println("First:", first)
	fmt.Println("Last: ", last)
}

Output:

First: fe80::
Last:  febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff