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// Copyright 2015 CNI 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 main
import (
"fmt"
"net"
"github.com/containernetworking/cni/pkg/ip"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/plugins/ipam/host-local/backend"
)
type IPAllocator struct {
start net.IP
end net.IP
conf *IPAMConfig
store backend.Store
}
func NewIPAllocator(conf *IPAMConfig, store backend.Store) (*IPAllocator, error) {
var (
start net.IP
end net.IP
err error
)
start, end, err = networkRange((*net.IPNet)(&conf.Subnet))
if err != nil {
return nil, err
}
// skip the .0 address
start = ip.NextIP(start)
if conf.RangeStart != nil {
if err := validateRangeIP(conf.RangeStart, (*net.IPNet)(&conf.Subnet)); err != nil {
return nil, err
}
start = conf.RangeStart
}
if conf.RangeEnd != nil {
if err := validateRangeIP(conf.RangeEnd, (*net.IPNet)(&conf.Subnet)); err != nil {
return nil, err
}
// RangeEnd is inclusive
end = ip.NextIP(conf.RangeEnd)
}
return &IPAllocator{start, end, conf, store}, nil
}
func validateRangeIP(ip net.IP, ipnet *net.IPNet) error {
if !ipnet.Contains(ip) {
return fmt.Errorf("%s not in network: %s", ip, ipnet)
}
return nil
}
// Returns newly allocated IP along with its config
func (a *IPAllocator) Get(id string) (*types.IPConfig, error) {
a.store.Lock()
defer a.store.Unlock()
gw := a.conf.Gateway
if gw == nil {
gw = ip.NextIP(a.conf.Subnet.IP)
}
var requestedIP net.IP
if a.conf.Args != nil {
requestedIP = a.conf.Args.IP
}
if requestedIP != nil {
if gw != nil && gw.Equal(a.conf.Args.IP) {
return nil, fmt.Errorf("requested IP must differ gateway IP")
}
subnet := net.IPNet{
IP: a.conf.Subnet.IP,
Mask: a.conf.Subnet.Mask,
}
err := validateRangeIP(requestedIP, &subnet)
if err != nil {
return nil, err
}
reserved, err := a.store.Reserve(id, requestedIP)
if err != nil {
return nil, err
}
if reserved {
return &types.IPConfig{
IP: net.IPNet{IP: requestedIP, Mask: a.conf.Subnet.Mask},
Gateway: gw,
Routes: a.conf.Routes,
}, nil
}
return nil, fmt.Errorf("requested IP address %q is not available in network: %s", requestedIP, a.conf.Name)
}
for cur := a.start; !cur.Equal(a.end); cur = ip.NextIP(cur) {
// don't allocate gateway IP
if gw != nil && cur.Equal(gw) {
continue
}
reserved, err := a.store.Reserve(id, cur)
if err != nil {
return nil, err
}
if reserved {
return &types.IPConfig{
IP: net.IPNet{IP: cur, Mask: a.conf.Subnet.Mask},
Gateway: gw,
Routes: a.conf.Routes,
}, nil
}
}
return nil, fmt.Errorf("no IP addresses available in network: %s", a.conf.Name)
}
// Releases all IPs allocated for the container with given ID
func (a *IPAllocator) Release(id string) error {
a.store.Lock()
defer a.store.Unlock()
return a.store.ReleaseByID(id)
}
func networkRange(ipnet *net.IPNet) (net.IP, net.IP, error) {
if ipnet.IP == nil {
return nil, nil, fmt.Errorf("missing field %q in IPAM configuration", "subnet")
}
ip := ipnet.IP.To4()
if ip == nil {
ip = ipnet.IP.To16()
if ip == nil {
return nil, nil, fmt.Errorf("IP not v4 nor v6")
}
}
if len(ip) != len(ipnet.Mask) {
return nil, nil, fmt.Errorf("IPNet IP and Mask version mismatch")
}
var end net.IP
for i := 0; i < len(ip); i++ {
end = append(end, ip[i]|^ipnet.Mask[i])
}
return ipnet.IP, end, nil
}
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