Bump github.com/containernetworking/plugins from 0.8.5 to 0.8.6

Bumps [github.com/containernetworking/plugins](https://github.com/containernetworking/plugins) from 0.8.5 to 0.8.6.
- [Release notes](https://github.com/containernetworking/plugins/releases)
- [Commits](https://github.com/containernetworking/plugins/compare/v0.8.5...v0.8.6)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/containernetworking/plugins/pkg/ip/link_linux.go

@@ -21,10 +21,12 @@ import (
 	"net"
 	"os"
 
-	"github.com/containernetworking/plugins/pkg/ns"
-	"github.com/containernetworking/plugins/pkg/utils/hwaddr"
 	"github.com/safchain/ethtool"
 	"github.com/vishvananda/netlink"
+
+	"github.com/containernetworking/plugins/pkg/ns"
+	"github.com/containernetworking/plugins/pkg/utils/hwaddr"
+	"github.com/containernetworking/plugins/pkg/utils/sysctl"
 )
 
 var (
@@ -158,6 +160,9 @@ func SetupVethWithName(contVethName, hostVethName string, mtu int, hostNS ns.Net
 		if err = netlink.LinkSetUp(hostVeth); err != nil {
 			return fmt.Errorf("failed to set %q up: %v", hostVethName, err)
 		}
+
+		// we want to own the routes for this interface
+		_, _ = sysctl.Sysctl(fmt.Sprintf("net/ipv6/conf/%s/accept_ra", hostVethName), "0")
 		return nil
 	})
 	if err != nil {
@@ -178,7 +183,7 @@ func SetupVeth(contVethName string, mtu int, hostNS ns.NetNS) (net.Interface, ne
 func DelLinkByName(ifName string) error {
 	iface, err := netlink.LinkByName(ifName)
 	if err != nil {
-		if err.Error() == "Link not found" {
+		if _, ok := err.(netlink.LinkNotFoundError); ok {
 			return ErrLinkNotFound
 		}
 		return fmt.Errorf("failed to lookup %q: %v", ifName, err)
@@ -195,7 +200,7 @@ func DelLinkByName(ifName string) error {
 func DelLinkByNameAddr(ifName string) ([]*net.IPNet, error) {
 	iface, err := netlink.LinkByName(ifName)
 	if err != nil {
-		if err != nil && err.Error() == "Link not found" {
+		if _, ok := err.(netlink.LinkNotFoundError); ok {
 			return nil, ErrLinkNotFound
 		}
 		return nil, fmt.Errorf("failed to lookup %q: %v", ifName, err)

vendor/github.com/containernetworking/plugins/pkg/ns/ns_linux.go

@@ -178,7 +178,16 @@ func (ns *netNS) Do(toRun func(NetNS) error) error {
 		if err = ns.Set(); err != nil {
 			return fmt.Errorf("error switching to ns %v: %v", ns.file.Name(), err)
 		}
-		defer threadNS.Set() // switch back
+		defer func() {
+			err := threadNS.Set() // switch back
+			if err == nil {
+				// Unlock the current thread only when we successfully switched back
+				// to the original namespace; otherwise leave the thread locked which
+				// will force the runtime to scrap the current thread, that is maybe
+				// not as optimal but at least always safe to do.
+				runtime.UnlockOSThread()
+			}
+		}()
 
 		return toRun(hostNS)
 	}
@@ -193,6 +202,10 @@ func (ns *netNS) Do(toRun func(NetNS) error) error {
 	var wg sync.WaitGroup
 	wg.Add(1)
 
+	// Start the callback in a new green thread so that if we later fail
+	// to switch the namespace back to the original one, we can safely
+	// leave the thread locked to die without a risk of the current thread
+	// left lingering with incorrect namespace.
 	var innerError error
 	go func() {
 		defer wg.Done()

vendor/github.com/containernetworking/plugins/pkg/utils/sysctl/sysctl_linux.go

@@ -0,0 +1,80 @@
+// 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 sysctl
+
+import (
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+)
+
+// Sysctl provides a method to set/get values from /proc/sys - in linux systems
+// new interface to set/get values of variables formerly handled by sysctl syscall
+// If optional `params` have only one string value - this function will
+// set this value into corresponding sysctl variable
+func Sysctl(name string, params ...string) (string, error) {
+	if len(params) > 1 {
+		return "", fmt.Errorf("unexcepted additional parameters")
+	} else if len(params) == 1 {
+		return setSysctl(name, params[0])
+	}
+	return getSysctl(name)
+}
+
+func getSysctl(name string) (string, error) {
+	fullName := filepath.Join("/proc/sys", toNormalName(name))
+	fullName = filepath.Clean(fullName)
+	data, err := ioutil.ReadFile(fullName)
+	if err != nil {
+		return "", err
+	}
+
+	return string(data[:len(data)-1]), nil
+}
+
+func setSysctl(name, value string) (string, error) {
+	fullName := filepath.Join("/proc/sys", toNormalName(name))
+	fullName = filepath.Clean(fullName)
+	if err := ioutil.WriteFile(fullName, []byte(value), 0644); err != nil {
+		return "", err
+	}
+
+	return getSysctl(name)
+}
+
+// Normalize names by using slash as separator
+// Sysctl names can use dots or slashes as separator:
+// - if dots are used, dots and slashes are interchanged.
+// - if slashes are used, slashes and dots are left intact.
+// Separator in use is determined by first occurrence.
+func toNormalName(name string) string {
+	interchange := false
+	for _, c := range name {
+		if c == '.' {
+			interchange = true
+			break
+		}
+		if c == '/' {
+			break
+		}
+	}
+
+	if interchange {
+		r := strings.NewReplacer(".", "/", "/", ".")
+		return r.Replace(name)
+	}
+	return name
+}