diff --git a/libpod/networking_slirp4netns.go b/libpod/networking_slirp4netns.go index c06d215e1a..e24b54032a 100644 --- a/libpod/networking_slirp4netns.go +++ b/libpod/networking_slirp4netns.go @@ -16,6 +16,7 @@ import ( "syscall" "time" + "github.com/containernetworking/plugins/pkg/ns" "github.com/containers/podman/v3/pkg/errorhandling" "github.com/containers/podman/v3/pkg/rootless" "github.com/containers/podman/v3/pkg/rootlessport" @@ -58,6 +59,8 @@ type slirp4netnsNetworkOptions struct { outboundAddr6 string } +const ipv6ConfDefaultAcceptDadSysctl = "/proc/sys/net/ipv6/conf/default/accept_dad" + func checkSlirpFlags(path string) (*slirpFeatures, error) { cmd := exec.Command(path, "--help") out, err := cmd.CombinedOutput() @@ -297,6 +300,39 @@ func (r *Runtime) setupSlirp4netns(ctr *Container) error { } cmd.Stdout = logFile cmd.Stderr = logFile + + var slirpReadyChan (chan struct{}) + + if netOptions.enableIPv6 { + slirpReadyChan = make(chan struct{}) + defer close(slirpReadyChan) + go func() { + err := ns.WithNetNSPath(netnsPath, func(_ ns.NetNS) error { + // Duplicate Address Detection slows the ipv6 setup down for 1-2 seconds. + // Since slirp4netns is run it is own namespace and not directly routed + // we can skip this to make the ipv6 address immediately available. + // We change the default to make sure the slirp tap interface gets the + // correct value assigned so DAD is disabled for it + // Also make sure to change this value back to the original after slirp4netns + // is ready in case users rely on this sysctl. + orgValue, err := ioutil.ReadFile(ipv6ConfDefaultAcceptDadSysctl) + if err != nil { + return err + } + err = ioutil.WriteFile(ipv6ConfDefaultAcceptDadSysctl, []byte("0"), 0644) + if err != nil { + return err + } + // wait for slirp to finish setup + <-slirpReadyChan + return ioutil.WriteFile(ipv6ConfDefaultAcceptDadSysctl, orgValue, 0644) + }) + if err != nil { + logrus.Warnf("failed to set net.ipv6.conf.default.accept_dad sysctl: %v", err) + } + }() + } + if err := cmd.Start(); err != nil { return errors.Wrapf(err, "failed to start slirp4netns process") } @@ -310,6 +346,9 @@ func (r *Runtime) setupSlirp4netns(ctr *Container) error { if err := waitForSync(syncR, cmd, logFile, 1*time.Second); err != nil { return err } + if slirpReadyChan != nil { + slirpReadyChan <- struct{}{} + } // Set a default slirp subnet. Parsing a string with the net helper is easier than building the struct myself _, ctr.slirp4netnsSubnet, _ = net.ParseCIDR(defaultSlirp4netnsSubnet) diff --git a/test/e2e/run_networking_test.go b/test/e2e/run_networking_test.go index 84707732bc..8d3b19b887 100644 --- a/test/e2e/run_networking_test.go +++ b/test/e2e/run_networking_test.go @@ -357,6 +357,26 @@ var _ = Describe("Podman run networking", func() { Expect(ncBusy).To(ExitWithError()) }) + It("podman run slirp4netns verify net.ipv6.conf.default.accept_dad=0", func() { + session := podmanTest.Podman([]string{"run", "--network", "slirp4netns:enable_ipv6=true", ALPINE, "ip", "addr"}) + session.Wait(30) + Expect(session).Should(Exit(0)) + // check the ipv6 setup id done without delay (https://github.com/containers/podman/issues/11062) + Expect(session.OutputToString()).To(ContainSubstring("inet6 fd00::")) + + const ipv6ConfDefaultAcceptDadSysctl = "/proc/sys/net/ipv6/conf/all/accept_dad" + + cat := SystemExec("cat", []string{ipv6ConfDefaultAcceptDadSysctl}) + cat.Wait(30) + Expect(cat).Should(Exit(0)) + sysctlValue := cat.OutputToString() + + session = podmanTest.Podman([]string{"run", "--network", "slirp4netns:enable_ipv6=true", ALPINE, "cat", ipv6ConfDefaultAcceptDadSysctl}) + session.Wait(30) + Expect(session).Should(Exit(0)) + Expect(session.OutputToString()).To(Equal(sysctlValue)) + }) + It("podman run network expose host port 18082 to container port 8000 using slirp4netns port handler", func() { session := podmanTest.Podman([]string{"run", "--network", "slirp4netns:port_handler=slirp4netns", "-dt", "-p", "18082:8000", ALPINE, "/bin/sh"}) session.Wait(30)