114 lines
2.5 KiB
Go
114 lines
2.5 KiB
Go
// Copyright 2019 the Kilo 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 mesh
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import (
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"net"
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"sort"
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)
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// sortIPs sorts IPs so the result is stable.
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// It will first sort IPs by type, to prefer selecting
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// IPs of the same type, and then by value.
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func sortIPs(ips []*net.IPNet) {
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sort.Slice(ips, func(i, j int) bool {
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i4, j4 := ips[i].IP.To4(), ips[j].IP.To4()
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if i4 != nil && j4 == nil {
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return true
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}
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if j4 != nil && i4 == nil {
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return false
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}
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return ips[i].String() < ips[j].String()
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})
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}
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func isLocal(ip net.IP) bool {
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return ip.IsLoopback() || ip.IsLinkLocalMulticast() || ip.IsLinkLocalUnicast()
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}
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func isPublic(ip net.IP) bool {
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// Check RFC 1918 addresses.
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if ip4 := ip.To4(); ip4 != nil {
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switch {
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// Check for 10.0.0.0/8.
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case ip4[0] == 10:
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return false
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// Check for 172.16.0.0/12.
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case ip4[0] == 172 && ip4[1]&0xf0 == 0x10:
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return false
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// Check for 192.168.0.0/16.
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case ip4[0] == 192 && ip4[1] == 168:
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return false
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default:
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return true
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}
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}
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// Check RFC 4193 addresses.
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if len(ip) == net.IPv6len {
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switch {
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// Check for fd00::/8.
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case ip[0] == 0xfd && ip[1] == 0x00:
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return false
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default:
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return true
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}
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}
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return false
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}
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type allocator struct {
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bits int
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ones int
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cidr *net.IPNet
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current net.IP
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}
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func newAllocator(cidr net.IPNet) *allocator {
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ones, bits := cidr.Mask.Size()
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current := make(net.IP, len(cidr.IP))
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copy(current, cidr.IP)
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if ip4 := current.To4(); ip4 != nil {
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current = ip4
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}
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return &allocator{
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bits: bits,
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ones: ones,
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cidr: &cidr,
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current: current,
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}
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}
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func (a *allocator) next() *net.IPNet {
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if a.current == nil {
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return nil
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}
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for i := len(a.current) - 1; i >= 0; i-- {
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a.current[i]++
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// if we haven't overflowed, then we can exit.
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if a.current[i] != 0 {
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break
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}
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}
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if !a.cidr.Contains(a.current) {
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a.current = nil
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}
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ip := make(net.IP, len(a.current))
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copy(ip, a.current)
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return &net.IPNet{IP: ip, Mask: net.CIDRMask(a.ones, a.bits)}
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}
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