120 lines
2.3 KiB
Go
120 lines
2.3 KiB
Go
package cidr
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import (
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"bytes"
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"fmt"
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"math"
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"net"
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"sort"
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)
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// SuperNetting 合并网段
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func SuperNetting(ns []string) (*cidr, error) {
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num := len(ns)
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if num < 1 || (num&(num-1)) != 0 {
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return nil, fmt.Errorf("子网数量必须是2的次方")
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}
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mask := ""
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var cidrs []*cidr
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for _, n := range ns {
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// 检查子网CIDR有效性
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c, err := ParseCIDR(n)
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if err != nil {
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return nil, fmt.Errorf("网段%v格式错误", n)
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}
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cidrs = append(cidrs, c)
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// TODO 暂只考虑相同子网掩码的网段合并
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if len(mask) == 0 {
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mask = c.Mask()
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} else if c.Mask() != mask {
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return nil, fmt.Errorf("子网掩码不一致")
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}
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}
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AscSortCIDRs(cidrs)
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// 检查网段是否连续
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var network net.IP
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for _, c := range cidrs {
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if len(network) > 0 {
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if !network.Equal(c.ipNet.IP) {
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return nil, fmt.Errorf("必须是连续的网段")
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}
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}
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network = net.ParseIP(c.Broadcast())
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IncrIP(network)
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}
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// 子网掩码左移，得到共同的父网段
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c := cidrs[0]
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ones, bits := c.MaskSize()
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ones = ones - int(math.Log2(float64(num)))
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c.ipNet.Mask = net.CIDRMask(ones, bits)
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c.ipNet.IP.Mask(c.ipNet.Mask)
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return c, nil
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}
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// IncrIP IP地址自增
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func IncrIP(ip net.IP) {
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for i := len(ip) - 1; i >= 0; i-- {
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ip[i]++
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if ip[i] > 0 {
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break
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}
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}
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}
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// DecrIP IP地址自减
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func DecrIP(ip net.IP) {
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length := len(ip)
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for i := length - 1; i >= 0; i-- {
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ip[length-1]--
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if ip[length-1] < 0xFF {
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break
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}
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for j := 1; j < length; j++ {
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ip[length-j-1]--
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if ip[length-j-1] < 0xFF {
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return
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}
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}
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}
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}
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// Compare 比较IP大小 a等于b，返回0; a大于b，返回+1; a小于b，返回-1
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func Compare(a, b net.IP) int {
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return bytes.Compare(a, b)
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}
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// AscSortCIDRs 升序
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func AscSortCIDRs(cs []*cidr) {
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sort.Slice(cs, func(i, j int) bool {
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if n := bytes.Compare(cs[i].ipNet.IP, cs[j].ipNet.IP); n != 0 {
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return n < 0
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}
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if n := bytes.Compare(cs[i].ipNet.Mask, cs[j].ipNet.Mask); n != 0 {
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return n < 0
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}
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return false
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})
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}
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// DescSortCIDRs 降序
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func DescSortCIDRs(cs []*cidr) {
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sort.Slice(cs, func(i, j int) bool {
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if n := bytes.Compare(cs[i].ipNet.IP, cs[j].ipNet.IP); n != 0 {
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return n >= 0
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}
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if n := bytes.Compare(cs[i].ipNet.Mask, cs[j].ipNet.Mask); n != 0 {
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return n >= 0
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}
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return false
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})
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}
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