63a6dbcfd6
1. get the right next IP of addresses of first byte 0 2. refactor some methods to handle illegal IPs or IPNets 3. add some unit tests Signed-off-by: Bruce Ma <brucema19901024@gmail.com>
106 lines
2.4 KiB
Go
106 lines
2.4 KiB
Go
// Copyright 2015 CNI authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ip
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import (
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"math/big"
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"net"
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)
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// NextIP returns IP incremented by 1, if IP is invalid, return nil
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func NextIP(ip net.IP) net.IP {
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normalizedIP := normalizeIP(ip)
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if normalizedIP == nil {
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return nil
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}
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i := ipToInt(normalizedIP)
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return intToIP(i.Add(i, big.NewInt(1)), len(normalizedIP) == net.IPv6len)
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}
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// PrevIP returns IP decremented by 1, if IP is invalid, return nil
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func PrevIP(ip net.IP) net.IP {
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normalizedIP := normalizeIP(ip)
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if normalizedIP == nil {
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return nil
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}
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i := ipToInt(normalizedIP)
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return intToIP(i.Sub(i, big.NewInt(1)), len(normalizedIP) == net.IPv6len)
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}
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// Cmp compares two IPs, returning the usual ordering:
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// a < b : -1
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// a == b : 0
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// a > b : 1
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// incomparable : -2
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func Cmp(a, b net.IP) int {
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normalizedA := normalizeIP(a)
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normalizedB := normalizeIP(b)
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if len(normalizedA) == len(normalizedB) && len(normalizedA) != 0 {
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return ipToInt(normalizedA).Cmp(ipToInt(normalizedB))
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}
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return -2
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}
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func ipToInt(ip net.IP) *big.Int {
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return big.NewInt(0).SetBytes(ip)
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}
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func intToIP(i *big.Int, isIPv6 bool) net.IP {
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intBytes := i.Bytes()
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if len(intBytes) == net.IPv4len || len(intBytes) == net.IPv6len {
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return intBytes
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}
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if isIPv6 {
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return append(make([]byte, net.IPv6len-len(intBytes)), intBytes...)
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}
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return append(make([]byte, net.IPv4len-len(intBytes)), intBytes...)
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}
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// normalizeIP will normalize IP by family,
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// IPv4 : 4-byte form
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// IPv6 : 16-byte form
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// others : nil
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func normalizeIP(ip net.IP) net.IP {
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if ipTo4 := ip.To4(); ipTo4 != nil {
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return ipTo4
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}
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return ip.To16()
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}
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// Network masks off the host portion of the IP, if IPNet is invalid,
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// return nil
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func Network(ipn *net.IPNet) *net.IPNet {
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if ipn == nil {
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return nil
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}
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maskedIP := ipn.IP.Mask(ipn.Mask)
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if maskedIP == nil {
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return nil
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}
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return &net.IPNet{
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IP: maskedIP,
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Mask: ipn.Mask,
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}
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}
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