107 lines
2.7 KiB
Go
107 lines
2.7 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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"fmt"
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"runtime"
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"github.com/containernetworking/cni/pkg/ns"
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"github.com/containernetworking/cni/pkg/skel"
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"github.com/containernetworking/cni/pkg/version"
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"github.com/vishvananda/netlink"
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)
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type NetConf struct {
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Device string `json:"device"`
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}
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func init() {
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// this ensures that main runs only on main thread (thread group leader).
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// since namespace ops (unshare, setns) are done for a single thread, we
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// must ensure that the goroutine does not jump from OS thread to thread
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runtime.LockOSThread()
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}
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func loadConf(bytes []byte) (*NetConf, error) {
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n := &NetConf{}
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if err := json.Unmarshal(bytes, n); err != nil {
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return nil, fmt.Errorf("failed to load netconf: %v", err)
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}
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if n.Device == "" {
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return nil, fmt.Errorf(`"device" field is required. It specifies the host device to put into the pod`)
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}
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return n, nil
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}
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func cmdAdd(args *skel.CmdArgs) error {
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cfg, err := loadConf(args.StdinData)
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if err != nil {
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return err
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}
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containerNs, err := ns.GetNS(args.Netns)
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if err != nil {
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return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
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}
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defer containerNs.Close()
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return addLink(cfg.Device, containerNs)
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}
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func cmdDel(args *skel.CmdArgs) error {
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cfg, err := loadConf(args.StdinData)
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if err != nil {
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return err
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}
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containerNs, err := ns.GetNS(args.Netns)
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if err != nil {
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return fmt.Errorf("failed to open netns %q: %v", args.Netns, err)
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}
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defer containerNs.Close()
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return removeLink(cfg.Device, containerNs)
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}
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func addLink(name string, containerNs ns.NetNS) error {
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dev, err := netlink.LinkByName(name)
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if err != nil {
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return fmt.Errorf("failed to lookup %v: %v", name, err)
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}
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return netlink.LinkSetNsFd(dev, int(containerNs.Fd()))
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}
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func removeLink(name string, containerNs ns.NetNS) error {
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var dev netlink.Link
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err := containerNs.Do(func(_ ns.NetNS) error {
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d, err := netlink.LinkByName(name)
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if err != nil {
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return err
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}
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dev = d
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return nil
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})
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if err != nil {
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return err
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}
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defaultNs, err := ns.GetCurrentNS()
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if err != nil {
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return err
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}
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return netlink.LinkSetNsFd(dev, int(defaultNs.Fd()))
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}
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func main() {
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skel.PluginMain(cmdAdd, cmdDel, version.All)
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}
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