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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 (
"encoding/json"
"errors"
"fmt"
"runtime"
"github.com/containernetworking/cni/pkg/ip"
"github.com/containernetworking/cni/pkg/ipam"
"github.com/containernetworking/cni/pkg/ns"
"github.com/containernetworking/cni/pkg/skel"
"github.com/containernetworking/cni/pkg/types"
"github.com/containernetworking/cni/pkg/utils/sysctl"
"github.com/vishvananda/netlink"
)
const (
IPv4InterfaceArpProxySysctlTemplate = "net.ipv4.conf.%s.proxy_arp"
)
type NetConf struct {
types.NetConf
Master string `json:"master"`
Mode string `json:"mode"`
MTU int `json:"mtu"`
}
func init() {
// this ensures that main runs only on main thread (thread group leader).
// since namespace ops (unshare, setns) are done for a single thread, we
// must ensure that the goroutine does not jump from OS thread to thread
runtime.LockOSThread()
}
func loadConf(bytes []byte) (*NetConf, error) {
n := &NetConf{}
if err := json.Unmarshal(bytes, n); err != nil {
return nil, fmt.Errorf("failed to load netconf: %v", err)
}
if n.Master == "" {
return nil, fmt.Errorf(`"master" field is required. It specifies the host interface name to virtualize`)
}
return n, nil
}
func modeFromString(s string) (netlink.MacvlanMode, error) {
switch s {
case "", "bridge":
return netlink.MACVLAN_MODE_BRIDGE, nil
case "private":
return netlink.MACVLAN_MODE_PRIVATE, nil
case "vepa":
return netlink.MACVLAN_MODE_VEPA, nil
case "passthru":
return netlink.MACVLAN_MODE_PASSTHRU, nil
default:
return 0, fmt.Errorf("unknown macvlan mode: %q", s)
}
}
func createMacvlan(conf *NetConf, ifName string, netns ns.NetNS) error {
mode, err := modeFromString(conf.Mode)
if err != nil {
return err
}
m, err := netlink.LinkByName(conf.Master)
if err != nil {
return fmt.Errorf("failed to lookup master %q: %v", conf.Master, err)
}
// due to kernel bug we have to create with tmpName or it might
// collide with the name on the host and error out
tmpName, err := ip.RandomVethName()
if err != nil {
return err
}
mv := &netlink.Macvlan{
LinkAttrs: netlink.LinkAttrs{
MTU: conf.MTU,
Name: tmpName,
ParentIndex: m.Attrs().Index,
Namespace: netlink.NsFd(int(netns.Fd())),
},
Mode: mode,
}
if err := netlink.LinkAdd(mv); err != nil {
return fmt.Errorf("failed to create macvlan: %v", err)
}
return netns.Do(func(_ ns.NetNS) error {
// TODO: duplicate following lines for ipv6 support, when it will be added in other places
ipv4SysctlValueName := fmt.Sprintf(IPv4InterfaceArpProxySysctlTemplate, tmpName)
if _, err := sysctl.Sysctl(ipv4SysctlValueName, "1"); err != nil {
// remove the newly added link and ignore errors, because we already are in a failed state
_ = netlink.LinkDel(mv)
return fmt.Errorf("failed to set proxy_arp on newly added interface %q: %v", tmpName, err)
}
err := renameLink(tmpName, ifName)
if err != nil {
_ = netlink.LinkDel(mv)
return fmt.Errorf("failed to rename macvlan to %q: %v", ifName, err)
}
return nil
})
}
func cmdAdd(args *skel.CmdArgs) error {
n, err := loadConf(args.StdinData)
if err != nil {
return err
}
netns, err := ns.GetNS(args.Netns)
if err != nil {
return fmt.Errorf("failed to open netns %q: %v", netns, err)
}
defer netns.Close()
if err = createMacvlan(n, args.IfName, netns); err != nil {
return err
}
// run the IPAM plugin and get back the config to apply
result, err := ipam.ExecAdd(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
if result.IP4 == nil {
return errors.New("IPAM plugin returned missing IPv4 config")
}
err = netns.Do(func(_ ns.NetNS) error {
return ipam.ConfigureIface(args.IfName, result)
})
if err != nil {
return err
}
result.DNS = n.DNS
return result.Print()
}
func cmdDel(args *skel.CmdArgs) error {
n, err := loadConf(args.StdinData)
if err != nil {
return err
}
err = ipam.ExecDel(n.IPAM.Type, args.StdinData)
if err != nil {
return err
}
if args.Netns == "" {
return nil
}
return ns.WithNetNSPath(args.Netns, func(_ ns.NetNS) error {
return ip.DelLinkByName(args.IfName)
})
}
func renameLink(curName, newName string) error {
link, err := netlink.LinkByName(curName)
if err != nil {
return err
}
return netlink.LinkSetName(link, newName)
}
func main() {
skel.PluginMain(cmdAdd, cmdDel)
}
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