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-rw-r--r--libpod/networking_slirp4netns.go40
1 files changed, 30 insertions, 10 deletions
diff --git a/libpod/networking_slirp4netns.go b/libpod/networking_slirp4netns.go
index 690f0c1fa..cc44f78f7 100644
--- a/libpod/networking_slirp4netns.go
+++ b/libpod/networking_slirp4netns.go
@@ -13,6 +13,7 @@ import (
"path/filepath"
"strconv"
"strings"
+ "sync"
"syscall"
"time"
@@ -302,11 +303,15 @@ func (r *Runtime) setupSlirp4netns(ctr *Container, netns ns.NetNS) error {
cmd.Stdout = logFile
cmd.Stderr = logFile
- var slirpReadyChan (chan struct{})
-
+ var slirpReadyWg, netnsReadyWg *sync.WaitGroup
if netOptions.enableIPv6 {
- slirpReadyChan = make(chan struct{})
- defer close(slirpReadyChan)
+ // use two wait groups to make sure we set the sysctl before
+ // starting slirp and reset it only after slirp is ready
+ slirpReadyWg = &sync.WaitGroup{}
+ netnsReadyWg = &sync.WaitGroup{}
+ slirpReadyWg.Add(1)
+ netnsReadyWg.Add(1)
+
go func() {
err := ns.WithNetNSPath(netnsPath, func(_ ns.NetNS) error {
// Duplicate Address Detection slows the ipv6 setup down for 1-2 seconds.
@@ -318,23 +323,37 @@ func (r *Runtime) setupSlirp4netns(ctr *Container, netns ns.NetNS) error {
// is ready in case users rely on this sysctl.
orgValue, err := ioutil.ReadFile(ipv6ConfDefaultAcceptDadSysctl)
if err != nil {
+ netnsReadyWg.Done()
+ // on ipv6 disabled systems the sysctl does not exists
+ // so we should not error
+ if errors.Is(err, os.ErrNotExist) {
+ return nil
+ }
return err
}
err = ioutil.WriteFile(ipv6ConfDefaultAcceptDadSysctl, []byte("0"), 0644)
+ netnsReadyWg.Done()
if err != nil {
return err
}
- // wait for slirp to finish setup
- <-slirpReadyChan
+
+ // wait until slirp4nets is ready before reseting this value
+ slirpReadyWg.Wait()
return ioutil.WriteFile(ipv6ConfDefaultAcceptDadSysctl, orgValue, 0644)
})
if err != nil {
logrus.Warnf("failed to set net.ipv6.conf.default.accept_dad sysctl: %v", err)
}
}()
+
+ // wait until we set the sysctl
+ netnsReadyWg.Wait()
}
if err := cmd.Start(); err != nil {
+ if netOptions.enableIPv6 {
+ slirpReadyWg.Done()
+ }
return errors.Wrapf(err, "failed to start slirp4netns process")
}
defer func() {
@@ -344,11 +363,12 @@ func (r *Runtime) setupSlirp4netns(ctr *Container, netns ns.NetNS) error {
}
}()
- if err := waitForSync(syncR, cmd, logFile, 1*time.Second); err != nil {
- return err
+ err = waitForSync(syncR, cmd, logFile, 1*time.Second)
+ if netOptions.enableIPv6 {
+ slirpReadyWg.Done()
}
- if slirpReadyChan != nil {
- slirpReadyChan <- struct{}{}
+ if err != nil {
+ return err
}
// Set a default slirp subnet. Parsing a string with the net helper is easier than building the struct myself