rootless netns, one netns per libpod tmp dir

The netns cleanup code is checking if there are running containers, this
can fail if you run several libpod instances with diffrent root/runroot.
To fix it we use one netns for each libpod instances. To prevent name
conflicts we use a hash from the static dir as part of the name.

Previously this worked because we would use the CNI files to check if
the netns was still in use. but this is no longer possible with netavark.

[NO NEW TESTS NEEDED]

Fixes containers#12306

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

libpod/networking_linux.go

@@ -4,6 +4,7 @@ package libpod
 
 import (
 	"crypto/rand"
+	"crypto/sha1"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -400,10 +401,7 @@ func (r *Runtime) GetRootlessNetNs(new bool) (*RootlessNetNS, error) {
 		return nil, nil
 	}
 	var rootlessNetNS *RootlessNetNS
-	runDir, err := util.GetRuntimeDir()
-	if err != nil {
-		return nil, err
-	}
+	runDir := r.config.Engine.TmpDir
 
 	lfile := filepath.Join(runDir, "rootless-netns.lock")
 	lock, err := lockfile.GetLockfile(lfile)
@@ -429,16 +427,24 @@ func (r *Runtime) GetRootlessNetNs(new bool) (*RootlessNetNS, error) {
 	if err != nil {
 		return nil, err
 	}
-	path := filepath.Join(nsDir, rootlessNetNsName)
+
+	// create a hash from the static dir
+	// the cleanup will check if there are running containers
+	// if you run a several libpod instances with different root/runroot directories this check will fail
+	// we want one netns for each libpod static dir so we use the hash to prevent name collisions
+	hash := sha1.Sum([]byte(r.config.Engine.StaticDir))
+	netnsName := fmt.Sprintf("%s-%x", rootlessNetNsName, hash[:10])
+
+	path := filepath.Join(nsDir, netnsName)
 	ns, err := ns.GetNS(path)
 	if err != nil {
 		if !new {
 			// return a error if we could not get the namespace and should no create one
 			return nil, errors.Wrap(err, "error getting rootless network namespace")
 		}
 		// create a new namespace
-		logrus.Debug("creating rootless network namespace")
-		ns, err = netns.NewNSWithName(rootlessNetNsName)
+		logrus.Debugf("creating rootless network namespace with name %q", netnsName)
+		ns, err = netns.NewNSWithName(netnsName)
 		if err != nil {
 			return nil, errors.Wrap(err, "error creating rootless network namespace")
 		}