150 lines
3.7 KiB
Go
150 lines
3.7 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package node
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import (
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"encoding/binary"
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"fmt"
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"math/big"
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"net"
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"sync"
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)
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type cidrSet struct {
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sync.Mutex
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clusterCIDR *net.IPNet
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clusterIP net.IP
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clusterMaskSize int
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maxCIDRs int
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nextCandidate int
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used big.Int
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subNetMaskSize int
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}
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func newCIDRSet(clusterCIDR *net.IPNet, subNetMaskSize int) *cidrSet {
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clusterMask := clusterCIDR.Mask
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clusterMaskSize, _ := clusterMask.Size()
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maxCIDRs := 1 << uint32(subNetMaskSize-clusterMaskSize)
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return &cidrSet{
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clusterCIDR: clusterCIDR,
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clusterIP: clusterCIDR.IP.To4(),
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clusterMaskSize: clusterMaskSize,
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maxCIDRs: maxCIDRs,
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subNetMaskSize: subNetMaskSize,
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}
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}
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func (s *cidrSet) allocateNext() (*net.IPNet, error) {
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s.Lock()
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defer s.Unlock()
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nextUnused := -1
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for i := 0; i < s.maxCIDRs; i++ {
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candidate := (i + s.nextCandidate) % s.maxCIDRs
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if s.used.Bit(candidate) == 0 {
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nextUnused = candidate
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break
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}
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}
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if nextUnused == -1 {
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return nil, errCIDRRangeNoCIDRsRemaining
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}
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s.nextCandidate = (nextUnused + 1) % s.maxCIDRs
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s.used.SetBit(&s.used, nextUnused, 1)
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j := uint32(nextUnused) << uint32(32-s.subNetMaskSize)
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ipInt := (binary.BigEndian.Uint32(s.clusterIP)) | j
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ip := make([]byte, 4)
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binary.BigEndian.PutUint32(ip, ipInt)
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return &net.IPNet{
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IP: ip,
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Mask: net.CIDRMask(s.subNetMaskSize, 32),
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}, nil
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}
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func (s *cidrSet) getBeginingAndEndIndices(cidr *net.IPNet) (begin, end int, err error) {
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begin, end = 0, s.maxCIDRs
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cidrMask := cidr.Mask
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maskSize, _ := cidrMask.Size()
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if !s.clusterCIDR.Contains(cidr.IP.Mask(s.clusterCIDR.Mask)) && !cidr.Contains(s.clusterCIDR.IP.Mask(cidr.Mask)) {
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return -1, -1, fmt.Errorf("cidr %v is out the range of cluster cidr %v", cidr, s.clusterCIDR)
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}
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if s.clusterMaskSize < maskSize {
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subNetMask := net.CIDRMask(s.subNetMaskSize, 32)
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begin, err = s.getIndexForCIDR(&net.IPNet{
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IP: cidr.IP.To4().Mask(subNetMask),
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Mask: subNetMask,
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})
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if err != nil {
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return -1, -1, err
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}
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ip := make([]byte, 4)
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ipInt := binary.BigEndian.Uint32(cidr.IP) | (^binary.BigEndian.Uint32(cidr.Mask))
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binary.BigEndian.PutUint32(ip, ipInt)
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end, err = s.getIndexForCIDR(&net.IPNet{
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IP: net.IP(ip).To4().Mask(subNetMask),
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Mask: subNetMask,
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})
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if err != nil {
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return -1, -1, err
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}
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}
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return begin, end, nil
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}
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func (s *cidrSet) release(cidr *net.IPNet) error {
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begin, end, err := s.getBeginingAndEndIndices(cidr)
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if err != nil {
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return err
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}
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s.Lock()
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defer s.Unlock()
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for i := begin; i <= end; i++ {
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s.used.SetBit(&s.used, i, 0)
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}
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return nil
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}
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func (s *cidrSet) occupy(cidr *net.IPNet) (err error) {
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begin, end, err := s.getBeginingAndEndIndices(cidr)
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if err != nil {
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return err
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}
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s.Lock()
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defer s.Unlock()
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for i := begin; i <= end; i++ {
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s.used.SetBit(&s.used, i, 1)
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}
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return nil
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}
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func (s *cidrSet) getIndexForCIDR(cidr *net.IPNet) (int, error) {
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cidrIndex := (binary.BigEndian.Uint32(s.clusterIP) ^ binary.BigEndian.Uint32(cidr.IP.To4())) >> uint32(32-s.subNetMaskSize)
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if cidrIndex >= uint32(s.maxCIDRs) {
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return 0, fmt.Errorf("CIDR: %v is out of the range of CIDR allocator", cidr)
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}
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return int(cidrIndex), nil
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}
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