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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.
// This is a "meta-plugin". It reads in its own netconf, it does not create
// any network interface but just changes the network sysctl.
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"path/filepath"
"strings"
"github.com/containernetworking/cni/pkg/ns"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
)
// TuningConf represents the network tuning configuration.
type TuningConf struct {
types.NetConf
SysCtl map[string]string `json:"sysctl"`
}
func cmdAdd(args *skel.CmdArgs) error {
tuningConf := TuningConf{}
if err := json.Unmarshal(args.StdinData, &tuningConf); err != nil {
return fmt.Errorf("failed to load netconf: %v", err)
}
// The directory /proc/sys/net is per network namespace. Enter in the
// network namespace before writing on it.
err := ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
for key, value := range tuningConf.SysCtl {
fileName := filepath.Join("/proc/sys", strings.Replace(key, ".", "/", -1))
fileName = filepath.Clean(fileName)
// Refuse to modify sysctl parameters that don't belong
// to the network subsystem.
if !strings.HasPrefix(fileName, "/proc/sys/net/") {
return fmt.Errorf("invalid net sysctl key: %q", key)
}
content := []byte(value)
err := ioutil.WriteFile(fileName, content, 0644)
if err != nil {
return err
}
}
return nil
})
if err != nil {
return err
}
result := types.Result{}
return result.Print()
}
func cmdDel(args *skel.CmdArgs) error {
// TODO: the settings are not reverted to the previous values. Reverting the
// settings is not useful when the whole container goes away but it could be
// useful in scenarios where plugins are added and removed at runtime.
return nil
}
func main() {
skel.PluginMain(cmdAdd, cmdDel)
}
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