77 lines
2 KiB
Go
77 lines
2 KiB
Go
// Copyright (c) HashiCorp, Inc.
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// SPDX-License-Identifier: MPL-2.0
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package parseip
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import (
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"strings"
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"k8s.io/utils/net"
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)
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// In Go 1.17 the behaviour of net.ParseIP and net.ParseCIDR changed
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// (https://golang.org/doc/go1.17#net) so that leading zeros in the input results
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// in an error. This package contains helpers that strip leading zeroes so as
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// to avoid those errors.
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// You should probably not be using anything here unless you've found a new place
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// where IPs/CIDRs are read from storage and re-parsed.
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// trimLeadingZeroes returns its input trimmed of any leading zeroes.
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func trimLeadingZeroes(s string) string {
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for i, r := range s {
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if r == '0' {
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continue
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}
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return s[i:]
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}
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return ""
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}
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// trimLeadingZeroesIPv4 takes an IPv4 string and returns the input
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// trimmed of any excess leading zeroes in each octet.
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func trimLeadingZeroesIPv4(s string) string {
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if len(s) == 0 {
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return s
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}
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pieces := strings.Split(s, ".")
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var sb strings.Builder
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for i, piece := range pieces {
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trimmed := trimLeadingZeroes(piece)
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if trimmed == "" && len(piece) > 0 {
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sb.WriteByte('0')
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} else {
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sb.WriteString(trimmed)
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}
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if i != len(pieces)-1 {
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sb.WriteByte('.')
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}
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}
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return sb.String()
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}
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// trimLeadingZeroesIP does the same work as trimLeadingZeroesIPv4 but also accepts
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// an IPv6 address that may contain an IPv4 address representation. Only decimal
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// IPv4 addresses get zero-stripped.
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func trimLeadingZeroesIP(s string) string {
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for i := len(s) - 1; i >= 0; i-- {
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if s[i] == ':' && net.ParseIPSloppy(s[i+1:]) != nil {
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return s[:i+1] + trimLeadingZeroesIPv4(s[i+1:])
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}
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}
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return trimLeadingZeroesIPv4(s)
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}
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// TrimLeadingZeroesCIDR does the same thing as trimLeadingZeroesIP but expects
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// a CIDR address as input. If the input isn't a valid CIDR address, it is returned
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// unchanged.
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func TrimLeadingZeroesCIDR(s string) string {
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pieces := strings.Split(s, "/")
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if len(pieces) != 2 {
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return s
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}
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pieces[0] = trimLeadingZeroesIP(pieces[0])
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return strings.Join(pieces, "/")
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}
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