dummy: Create a Dummy CNI plugin that creates a virtual interface.
Leverages the Linux dummy interface type to create network interfaces that permists routing packets through the Linux kernel without them being transmitted. This solution allows use of arbitrary non-loopback IP addresses within the container. Related to #466 Signed-off-by: Mircea Iordache-Sica <mircea@arista.com>
This commit is contained in:
Mircea Iordache-Sica
392
plugins/main/dummy/dummy_test.go
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392
plugins/main/dummy/dummy_test.go
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// Copyright 2022 Arista Networks
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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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"os"
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"strings"
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"syscall"
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"github.com/containernetworking/cni/pkg/skel"
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"github.com/containernetworking/cni/pkg/types"
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types020 "github.com/containernetworking/cni/pkg/types/020"
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types040 "github.com/containernetworking/cni/pkg/types/040"
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types100 "github.com/containernetworking/cni/pkg/types/100"
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"github.com/containernetworking/plugins/pkg/ns"
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"github.com/containernetworking/plugins/pkg/testutils"
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"github.com/containernetworking/plugins/plugins/ipam/host-local/backend/allocator"
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"github.com/vishvananda/netlink"
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. "github.com/onsi/ginkgo"
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. "github.com/onsi/gomega"
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)
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const MASTER_NAME = "eth0"
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type Net struct {
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Name string `json:"name"`
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CNIVersion string `json:"cniVersion"`
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Type string `json:"type,omitempty"`
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IPAM *allocator.IPAMConfig `json:"ipam"`
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RawPrevResult map[string]interface{} `json:"prevResult,omitempty"`
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PrevResult types100.Result `json:"-"`
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}
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func buildOneConfig(netName string, cniVersion string, orig *Net, prevResult types.Result) (*Net, error) {
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var err error
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inject := map[string]interface{}{
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"name": netName,
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"cniVersion": cniVersion,
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}
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// Add previous plugin result
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if prevResult != nil {
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inject["prevResult"] = prevResult
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}
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// Ensure every config uses the same name and version
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config := make(map[string]interface{})
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confBytes, err := json.Marshal(orig)
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if err != nil {
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return nil, err
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}
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err = json.Unmarshal(confBytes, &config)
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if err != nil {
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return nil, fmt.Errorf("unmarshal existing network bytes: %s", err)
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}
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for key, value := range inject {
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config[key] = value
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}
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newBytes, err := json.Marshal(config)
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if err != nil {
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return nil, err
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}
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conf := &Net{}
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if err := json.Unmarshal(newBytes, &conf); err != nil {
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return nil, fmt.Errorf("error parsing configuration: %s", err)
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}
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return conf, nil
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}
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type tester interface {
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// verifyResult minimally verifies the Result and returns the interface's MAC address
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verifyResult(result types.Result, name string) string
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}
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type testerBase struct{}
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type testerV10x testerBase
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type testerV04x testerBase
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type testerV03x testerBase
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type testerV01xOr02x testerBase
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func newTesterByVersion(version string) tester {
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switch {
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case strings.HasPrefix(version, "1.0."):
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return &testerV10x{}
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case strings.HasPrefix(version, "0.4."):
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return &testerV04x{}
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case strings.HasPrefix(version, "0.3."):
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return &testerV03x{}
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default:
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return &testerV01xOr02x{}
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}
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}
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// verifyResult minimally verifies the Result and returns the interface's MAC address
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func (t *testerV10x) verifyResult(result types.Result, name string) string {
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r, err := types100.GetResult(result)
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Expect(err).NotTo(HaveOccurred())
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Expect(len(r.Interfaces)).To(Equal(1))
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Expect(r.Interfaces[0].Name).To(Equal(name))
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Expect(len(r.IPs)).To(Equal(1))
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return r.Interfaces[0].Mac
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}
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func verify0403(result types.Result, name string) string {
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r, err := types040.GetResult(result)
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Expect(err).NotTo(HaveOccurred())
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Expect(len(r.Interfaces)).To(Equal(1))
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Expect(r.Interfaces[0].Name).To(Equal(name))
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Expect(len(r.IPs)).To(Equal(1))
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return r.Interfaces[0].Mac
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}
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// verifyResult minimally verifies the Result and returns the interface's MAC address
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func (t *testerV04x) verifyResult(result types.Result, name string) string {
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return verify0403(result, name)
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}
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// verifyResult minimally verifies the Result and returns the interface's MAC address
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func (t *testerV03x) verifyResult(result types.Result, name string) string {
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return verify0403(result, name)
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}
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// verifyResult minimally verifies the Result and returns the interface's MAC address
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func (t *testerV01xOr02x) verifyResult(result types.Result, name string) string {
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r, err := types020.GetResult(result)
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Expect(err).NotTo(HaveOccurred())
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Expect(r.IP4.IP.IP).NotTo(BeNil())
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Expect(r.IP6).To(BeNil())
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// 0.2 and earlier don't return MAC address
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return ""
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}
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var _ = Describe("dummy Operations", func() {
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var originalNS, targetNS ns.NetNS
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var dataDir string
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BeforeEach(func() {
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// Create a new NetNS so we don't modify the host
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var err error
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originalNS, err = testutils.NewNS()
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Expect(err).NotTo(HaveOccurred())
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targetNS, err = testutils.NewNS()
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Expect(err).NotTo(HaveOccurred())
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dataDir, err = ioutil.TempDir("", "dummy_test")
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Expect(err).NotTo(HaveOccurred())
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err = originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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// Add master
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err = netlink.LinkAdd(&netlink.Dummy{
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LinkAttrs: netlink.LinkAttrs{
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Name: MASTER_NAME,
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},
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})
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Expect(err).NotTo(HaveOccurred())
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m, err := netlink.LinkByName(MASTER_NAME)
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Expect(err).NotTo(HaveOccurred())
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err = netlink.LinkSetUp(m)
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Expect(err).NotTo(HaveOccurred())
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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})
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AfterEach(func() {
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Expect(os.RemoveAll(dataDir)).To(Succeed())
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Expect(originalNS.Close()).To(Succeed())
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Expect(testutils.UnmountNS(originalNS)).To(Succeed())
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Expect(targetNS.Close()).To(Succeed())
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Expect(testutils.UnmountNS(targetNS)).To(Succeed())
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})
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for _, ver := range testutils.AllSpecVersions {
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// Redefine ver inside for scope so real value is picked up by each dynamically defined It()
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// See Gingkgo's "Patterns for dynamically generating tests" documentation.
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ver := ver
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It(fmt.Sprintf("[%s] creates an dummy link in a non-default namespace", ver), func() {
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conf := &types.NetConf{
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CNIVersion: ver,
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Name: "testConfig",
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Type: "dummy",
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}
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// Create dummy in other namespace
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err := originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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_, err := createDummy(conf, "foobar0", targetNS)
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Expect(err).NotTo(HaveOccurred())
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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// Make sure dummy link exists in the target namespace
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err = targetNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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link, err := netlink.LinkByName("foobar0")
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Expect(err).NotTo(HaveOccurred())
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Expect(link.Attrs().Name).To(Equal("foobar0"))
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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})
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It(fmt.Sprintf("[%s] configures and deconfigures a dummy link with ADD/CHECK/DEL", ver), func() {
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const IFNAME = "dummy0"
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conf := fmt.Sprintf(`{
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"cniVersion": "%s",
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"name": "dummyTestv4",
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"type": "dummy",
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"ipam": {
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"type": "host-local",
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"subnet": "10.1.2.0/24",
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"dataDir": "%s"
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}
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}`, ver, dataDir)
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args := &skel.CmdArgs{
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ContainerID: "contDummy",
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Netns: targetNS.Path(),
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IfName: IFNAME,
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StdinData: []byte(conf),
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}
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t := newTesterByVersion(ver)
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var result types.Result
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var macAddress string
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err := originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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var err error
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result, _, err = testutils.CmdAddWithArgs(args, func() error {
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return cmdAdd(args)
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})
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Expect(err).NotTo(HaveOccurred())
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macAddress = t.verifyResult(result, IFNAME)
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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// Make sure dummy link exists in the target namespace
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err = targetNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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link, err := netlink.LinkByName(IFNAME)
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Expect(err).NotTo(HaveOccurred())
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Expect(link.Attrs().Name).To(Equal(IFNAME))
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if macAddress != "" {
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hwaddr, err := net.ParseMAC(macAddress)
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Expect(err).NotTo(HaveOccurred())
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Expect(link.Attrs().HardwareAddr).To(Equal(hwaddr))
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}
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addrs, err := netlink.AddrList(link, syscall.AF_INET)
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Expect(err).NotTo(HaveOccurred())
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Expect(len(addrs)).To(Equal(1))
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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// call CmdCheck
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n := &Net{}
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err = json.Unmarshal([]byte(conf), &n)
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Expect(err).NotTo(HaveOccurred())
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n.IPAM, _, err = allocator.LoadIPAMConfig([]byte(conf), "")
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Expect(err).NotTo(HaveOccurred())
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newConf, err := buildOneConfig("dummyTestv4", ver, n, result)
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Expect(err).NotTo(HaveOccurred())
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confString, err := json.Marshal(newConf)
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Expect(err).NotTo(HaveOccurred())
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args.StdinData = confString
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// CNI Check dummy in the target namespace
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err = originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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return testutils.CmdCheckWithArgs(args, func() error { return cmdCheck(args) })
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})
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if testutils.SpecVersionHasCHECK(ver) {
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Expect(err).NotTo(HaveOccurred())
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} else {
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Expect(err).To(MatchError("config version does not allow CHECK"))
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}
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args.StdinData = []byte(conf)
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err = originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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err = testutils.CmdDelWithArgs(args, func() error {
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return cmdDel(args)
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})
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Expect(err).NotTo(HaveOccurred())
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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// Make sure dummy link has been deleted
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err = targetNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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link, err := netlink.LinkByName(IFNAME)
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Expect(err).To(HaveOccurred())
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Expect(link).To(BeNil())
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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// DEL can be called multiple times, make sure no error is returned
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// if the device is already removed.
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err = originalNS.Do(func(ns.NetNS) error {
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defer GinkgoRecover()
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err = testutils.CmdDelWithArgs(args, func() error {
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return cmdDel(args)
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})
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Expect(err).NotTo(HaveOccurred())
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return nil
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})
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Expect(err).NotTo(HaveOccurred())
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})
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It(fmt.Sprintf("[%s] fails to create dummy link with no ipam", ver), func() {
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var err error
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const confFmt = `{
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"cniVersion": "%s",
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"name": "mynet",
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"type": "dummy"
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}`
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args := &skel.CmdArgs{
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ContainerID: "dummyCont",
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Netns: "/var/run/netns/test",
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IfName: "dummy0",
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StdinData: []byte(fmt.Sprintf(confFmt, ver)),
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}
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_ = originalNS.Do(func(netNS ns.NetNS) error {
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defer GinkgoRecover()
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_, _, err = testutils.CmdAddWithArgs(args, func() error {
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return cmdAdd(args)
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})
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Expect(err).To(Equal(errors.New("dummy interface requires an IPAM configuration")))
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return nil
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})
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})
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}
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})
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