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// Copyright 2016 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 (
"encoding/json"
"errors"
"fmt"
"net"
"github.com/vishvananda/netlink"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/pkg/types/current"
"github.com/containernetworking/cni/pkg/version"
"github.com/containernetworking/plugins/pkg/ns"
bv "github.com/containernetworking/plugins/pkg/utils/buildversion"
)
func parseNetConf(bytes []byte) (*types.NetConf, error) {
conf := &types.NetConf{}
if err := json.Unmarshal(bytes, conf); err != nil {
return nil, fmt.Errorf("failed to parse network config: %v", err)
}
if conf.RawPrevResult != nil {
if err := version.ParsePrevResult(conf); err != nil {
return nil, fmt.Errorf("failed to parse prevResult: %v", err)
}
if _, err := current.NewResultFromResult(conf.PrevResult); err != nil {
return nil, fmt.Errorf("failed to convert result to current version: %v", err)
}
}
return conf, nil
}
func cmdAdd(args *skel.CmdArgs) error {
conf, err := parseNetConf(args.StdinData)
if err != nil {
return err
}
var v4Addr, v6Addr *net.IPNet
args.IfName = "lo" // ignore config, this only works for loopback
err = ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
link, err := netlink.LinkByName(args.IfName)
if err != nil {
return err // not tested
}
err = netlink.LinkSetUp(link)
if err != nil {
return err // not tested
}
v4Addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
if err != nil {
return err // not tested
}
if len(v4Addrs) != 0 {
v4Addr = v4Addrs[0].IPNet
// sanity check that this is a loopback address
for _, addr := range v4Addrs {
if !addr.IP.IsLoopback() {
return fmt.Errorf("loopback interface found with non-loopback address %q", addr.IP)
}
}
}
v6Addrs, err := netlink.AddrList(link, netlink.FAMILY_V6)
if err != nil {
return err // not tested
}
if len(v6Addrs) != 0 {
v6Addr = v6Addrs[0].IPNet
// sanity check that this is a loopback address
for _, addr := range v6Addrs {
if !addr.IP.IsLoopback() {
return fmt.Errorf("loopback interface found with non-loopback address %q", addr.IP)
}
}
}
return nil
})
if err != nil {
return err // not tested
}
var result types.Result
if conf.PrevResult != nil {
// If loopback has previous result which passes from previous CNI plugin,
// loopback should pass it transparently
result = conf.PrevResult
} else {
loopbackInterface := &current.Interface{Name: args.IfName, Mac: "00:00:00:00:00:00", Sandbox: args.Netns}
r := &current.Result{CNIVersion: conf.CNIVersion, Interfaces: []*current.Interface{loopbackInterface}}
if v4Addr != nil {
r.IPs = append(r.IPs, &current.IPConfig{
Version: "4",
Interface: current.Int(0),
Address: *v4Addr,
})
}
if v6Addr != nil {
r.IPs = append(r.IPs, &current.IPConfig{
Version: "6",
Interface: current.Int(0),
Address: *v6Addr,
})
}
result = r
}
return types.PrintResult(result, conf.CNIVersion)
}
func cmdDel(args *skel.CmdArgs) error {
if args.Netns == "" {
return nil
}
args.IfName = "lo" // ignore config, this only works for loopback
err := ns.WithNetNSPath(args.Netns, func(ns.NetNS) error {
link, err := netlink.LinkByName(args.IfName)
if err != nil {
return err // not tested
}
err = netlink.LinkSetDown(link)
if err != nil {
return err // not tested
}
return nil
})
if err != nil {
return err // not tested
}
return nil
}
func main() {
skel.PluginMain(cmdAdd, cmdCheck, cmdDel, version.All, bv.BuildString("loopback"))
}
func cmdCheck(args *skel.CmdArgs) error {
args.IfName = "lo" // ignore config, this only works for loopback
return ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
link, err := netlink.LinkByName(args.IfName)
if err != nil {
return err
}
if link.Attrs().Flags&net.FlagUp != net.FlagUp {
return errors.New("loopback interface is down")
}
return nil
})
}
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