/* Copyright 2016 The Kubernetes Authors. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. */ package node import ( "encoding/binary" "fmt" "math/big" "net" "sync" ) type cidrSet struct { sync.Mutex clusterCIDR *net.IPNet clusterIP net.IP clusterMaskSize int maxCIDRs int nextCandidate int used big.Int subNetMaskSize int } func newCIDRSet(clusterCIDR *net.IPNet, subNetMaskSize int) *cidrSet { clusterMask := clusterCIDR.Mask clusterMaskSize, _ := clusterMask.Size() maxCIDRs := 1 << uint32(subNetMaskSize-clusterMaskSize) return &cidrSet{ clusterCIDR: clusterCIDR, clusterIP: clusterCIDR.IP.To4(), clusterMaskSize: clusterMaskSize, maxCIDRs: maxCIDRs, subNetMaskSize: subNetMaskSize, } } func (s *cidrSet) allocateNext() (*net.IPNet, error) { s.Lock() defer s.Unlock() nextUnused := -1 for i := 0; i < s.maxCIDRs; i++ { candidate := (i + s.nextCandidate) % s.maxCIDRs if s.used.Bit(candidate) == 0 { nextUnused = candidate break } } if nextUnused == -1 { return nil, errCIDRRangeNoCIDRsRemaining } s.nextCandidate = (nextUnused + 1) % s.maxCIDRs s.used.SetBit(&s.used, nextUnused, 1) j := uint32(nextUnused) << uint32(32-s.subNetMaskSize) ipInt := (binary.BigEndian.Uint32(s.clusterIP)) | j ip := make([]byte, 4) binary.BigEndian.PutUint32(ip, ipInt) return &net.IPNet{ IP: ip, Mask: net.CIDRMask(s.subNetMaskSize, 32), }, nil } func (s *cidrSet) getBeginingAndEndIndices(cidr *net.IPNet) (begin, end int, err error) { begin, end = 0, s.maxCIDRs cidrMask := cidr.Mask maskSize, _ := cidrMask.Size() if !s.clusterCIDR.Contains(cidr.IP.Mask(s.clusterCIDR.Mask)) && !cidr.Contains(s.clusterCIDR.IP.Mask(cidr.Mask)) { return -1, -1, fmt.Errorf("cidr %v is out the range of cluster cidr %v", cidr, s.clusterCIDR) } if s.clusterMaskSize < maskSize { subNetMask := net.CIDRMask(s.subNetMaskSize, 32) begin, err = s.getIndexForCIDR(&net.IPNet{ IP: cidr.IP.To4().Mask(subNetMask), Mask: subNetMask, }) if err != nil { return -1, -1, err } ip := make([]byte, 4) ipInt := binary.BigEndian.Uint32(cidr.IP) | (^binary.BigEndian.Uint32(cidr.Mask)) binary.BigEndian.PutUint32(ip, ipInt) end, err = s.getIndexForCIDR(&net.IPNet{ IP: net.IP(ip).To4().Mask(subNetMask), Mask: subNetMask, }) if err != nil { return -1, -1, err } } return begin, end, nil } func (s *cidrSet) release(cidr *net.IPNet) error { begin, end, err := s.getBeginingAndEndIndices(cidr) if err != nil { return err } s.Lock() defer s.Unlock() for i := begin; i <= end; i++ { s.used.SetBit(&s.used, i, 0) } return nil } func (s *cidrSet) occupy(cidr *net.IPNet) (err error) { begin, end, err := s.getBeginingAndEndIndices(cidr) if err != nil { return err } s.Lock() defer s.Unlock() for i := begin; i <= end; i++ { s.used.SetBit(&s.used, i, 1) } return nil } func (s *cidrSet) getIndexForCIDR(cidr *net.IPNet) (int, error) { cidrIndex := (binary.BigEndian.Uint32(s.clusterIP) ^ binary.BigEndian.Uint32(cidr.IP.To4())) >> uint32(32-s.subNetMaskSize) if cidrIndex >= uint32(s.maxCIDRs) { return 0, fmt.Errorf("CIDR: %v is out of the range of CIDR allocator", cidr) } return int(cidrIndex), nil }