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// Copyright 2017 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 ip
import (
"fmt"
"syscall"
"time"
"github.com/vishvananda/netlink"
)
const SETTLE_INTERVAL = 50 * time.Millisecond
// SettleAddresses waits for all addresses on a link to leave tentative state.
// This is particularly useful for ipv6, where all addresses need to do DAD.
// There is no easy way to wait for this as an event, so just loop until the
// addresses are no longer tentative.
// If any addresses are still tentative after timeout seconds, then error.
func SettleAddresses(ifName string, timeout int) error {
link, err := netlink.LinkByName(ifName)
if err != nil {
return fmt.Errorf("failed to retrieve link: %v", err)
}
deadline := time.Now().Add(time.Duration(timeout) * time.Second)
for {
addrs, err := netlink.AddrList(link, netlink.FAMILY_ALL)
if err != nil {
return fmt.Errorf("could not list addresses: %v", err)
}
if len(addrs) == 0 {
return nil
}
ok := true
for _, addr := range addrs {
if addr.Flags&(syscall.IFA_F_TENTATIVE|syscall.IFA_F_DADFAILED) > 0 {
ok = false
break // Break out of the `range addrs`, not the `for`
}
}
if ok {
return nil
}
if time.Now().After(deadline) {
return fmt.Errorf("link %s still has tentative addresses after %d seconds",
ifName,
timeout)
}
time.Sleep(SETTLE_INTERVAL)
}
}
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