netdata/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package iprange

import (
    "bytes"
    "fmt"
    "math/big"
    "net"
)

// Family represents IP Range address-family.
type Family uint8

const (
    // V4Family is IPv4 address-family.
    V4Family Family = iota
    // V6Family is IPv6 address-family.
    V6Family
)

// Range represents an IP range.
type Range interface {
    Family() Family
    Contains(ip net.IP) bool
    Size() *big.Int
    fmt.Stringer
}

// New returns new IP Range.
// If it is not a valid range (start and end IPs have different address-families, or start > end),
// New returns nil.
func New(start, end net.IP) Range {
    if isV4RangeValid(start, end) {
        return v4Range{start: start, end: end}
    }
    if isV6RangeValid(start, end) {
        return v6Range{start: start, end: end}
    }
    return nil
}

type v4Range struct {
    start net.IP
    end   net.IP
}

// String returns the string form of the range.
func (r v4Range) String() string {
    return fmt.Sprintf("%s-%s", r.start, r.end)
}

// Family returns the range address family.
func (r v4Range) Family() Family {
    return V4Family
}

// Contains reports whether the range includes IP.
func (r v4Range) Contains(ip net.IP) bool {
    return bytes.Compare(ip, r.start) >= 0 && bytes.Compare(ip, r.end) <= 0
}

// Size reports the number of IP addresses in the range.
func (r v4Range) Size() *big.Int {
    return big.NewInt(v4ToInt(r.end) - v4ToInt(r.start) + 1)
}

type v6Range struct {
    start net.IP
    end   net.IP
}

// String returns the string form of the range.
func (r v6Range) String() string {
    return fmt.Sprintf("%s-%s", r.start, r.end)
}

// Family returns the range address family.
func (r v6Range) Family() Family {
    return V6Family
}

// Contains reports whether the range includes IP.
func (r v6Range) Contains(ip net.IP) bool {
    return bytes.Compare(ip, r.start) >= 0 && bytes.Compare(ip, r.end) <= 0
}

// Size reports the number of IP addresses in the range.
func (r v6Range) Size() *big.Int {
    size := big.NewInt(0)
    size.Add(size, big.NewInt(0).SetBytes(r.end))
    size.Sub(size, big.NewInt(0).SetBytes(r.start))
    size.Add(size, big.NewInt(1))
    return size
}

func v4ToInt(ip net.IP) int64 {
    ip = ip.To4()
    return int64(ip[0])<<24 | int64(ip[1])<<16 | int64(ip[2])<<8 | int64(ip[3])
}