
Don't lock around the Stop() operation though, as that may take a while and block other operations. That may mean we call Stop() multiple times, but the Lease object should handle that correctly itself.
181 lines
4.3 KiB
Go
181 lines
4.3 KiB
Go
// Copyright 2015 CNI 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 main
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import (
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"encoding/json"
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"errors"
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"fmt"
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"io/ioutil"
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"net"
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"net/http"
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"net/rpc"
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"os"
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"path/filepath"
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"runtime"
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"sync"
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"github.com/containernetworking/cni/pkg/skel"
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"github.com/containernetworking/cni/pkg/types"
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"github.com/containernetworking/cni/pkg/types/current"
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"github.com/coreos/go-systemd/activation"
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)
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const listenFdsStart = 3
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const resendCount = 3
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var errNoMoreTries = errors.New("no more tries")
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type DHCP struct {
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mux sync.Mutex
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leases map[string]*DHCPLease
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hostNetnsPrefix string
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}
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func newDHCP() *DHCP {
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return &DHCP{
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leases: make(map[string]*DHCPLease),
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}
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}
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// Allocate acquires an IP from a DHCP server for a specified container.
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// The acquired lease will be maintained until Release() is called.
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func (d *DHCP) Allocate(args *skel.CmdArgs, result *current.Result) error {
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conf := types.NetConf{}
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if err := json.Unmarshal(args.StdinData, &conf); err != nil {
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return fmt.Errorf("error parsing netconf: %v", err)
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}
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clientID := args.ContainerID + "/" + conf.Name
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hostNetns := d.hostNetnsPrefix + args.Netns
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l, err := AcquireLease(clientID, hostNetns, args.IfName)
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if err != nil {
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return err
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}
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ipn, err := l.IPNet()
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if err != nil {
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l.Stop()
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return err
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}
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d.setLease(args.ContainerID, conf.Name, l)
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result.IPs = []*current.IPConfig{{
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Version: "4",
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Address: *ipn,
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Gateway: l.Gateway(),
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}}
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result.Routes = l.Routes()
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return nil
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}
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// Release stops maintenance of the lease acquired in Allocate()
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// and sends a release msg to the DHCP server.
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func (d *DHCP) Release(args *skel.CmdArgs, reply *struct{}) error {
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conf := types.NetConf{}
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if err := json.Unmarshal(args.StdinData, &conf); err != nil {
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return fmt.Errorf("error parsing netconf: %v", err)
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}
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if l := d.getLease(args.ContainerID, conf.Name); l != nil {
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l.Stop()
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d.clearLease(args.ContainerID, conf.Name)
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}
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return nil
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}
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func (d *DHCP) getLease(contID, netName string) *DHCPLease {
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d.mux.Lock()
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defer d.mux.Unlock()
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// TODO(eyakubovich): hash it to avoid collisions
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l, ok := d.leases[contID+netName]
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if !ok {
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return nil
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}
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return l
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}
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func (d *DHCP) setLease(contID, netName string, l *DHCPLease) {
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d.mux.Lock()
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defer d.mux.Unlock()
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// TODO(eyakubovich): hash it to avoid collisions
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d.leases[contID+netName] = l
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}
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func (d *DHCP) clearLease(contID, netName string) {
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d.mux.Lock()
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defer d.mux.Unlock()
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// TODO(eyakubovich): hash it to avoid collisions
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delete(d.leases, contID+netName)
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}
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func getListener() (net.Listener, error) {
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l, err := activation.Listeners(true)
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if err != nil {
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return nil, err
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}
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switch {
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case len(l) == 0:
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if err := os.MkdirAll(filepath.Dir(socketPath), 0700); err != nil {
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return nil, err
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}
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return net.Listen("unix", socketPath)
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case len(l) == 1:
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if l[0] == nil {
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return nil, fmt.Errorf("LISTEN_FDS=1 but no FD found")
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}
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return l[0], nil
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default:
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return nil, fmt.Errorf("Too many (%v) FDs passed through socket activation", len(l))
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}
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}
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func runDaemon(pidfilePath string, hostPrefix string) error {
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// since other goroutines (on separate threads) will change namespaces,
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// ensure the RPC server does not get scheduled onto those
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runtime.LockOSThread()
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// Write the pidfile
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if pidfilePath != "" {
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if !filepath.IsAbs(pidfilePath) {
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return fmt.Errorf("Error writing pidfile %q: path not absolute", pidfilePath)
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}
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if err := ioutil.WriteFile(pidfilePath, []byte(fmt.Sprintf("%d", os.Getpid())), 0644); err != nil {
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return fmt.Errorf("Error writing pidfile %q: %v", pidfilePath, err)
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}
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}
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l, err := getListener()
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if err != nil {
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return fmt.Errorf("Error getting listener: %v", err)
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}
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dhcp := newDHCP()
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dhcp.hostNetnsPrefix = hostPrefix
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rpc.Register(dhcp)
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rpc.HandleHTTP()
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http.Serve(l, nil)
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return nil
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}
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