Move CIDR allocation logic away from nodecontroller.go

pkg/controller/node/cidr_set.go

@@ -0,0 +1,142 @@
+/*
+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) release(cidr *net.IPNet) error {
+	used, err := s.getIndexForCIDR(cidr)
+	if err != nil {
+		return err
+	}
+
+	s.Lock()
+	defer s.Unlock()
+	s.used.SetBit(&s.used, used, 0)
+
+	return nil
+}
+
+func (s *cidrSet) occupy(cidr *net.IPNet) (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 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 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 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
+}