rootless: support `podman network create` (CNI-in-slirp4netns)

Usage:
```
$ podman network create foo
$ podman run -d --name web --hostname web --network foo nginx:alpine
$ podman run --rm --network foo alpine wget -O - http://web.dns.podman
Connecting to web.dns.podman (10.88.4.6:80)
...
<h1>Welcome to nginx!</h1>
...
```

See contrib/rootless-cni-infra for the design.

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

1 files changed, 3 insertions, 1 deletions

diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index c41d81a2b..c3f07a48b 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -957,8 +957,10 @@ func (c *Container) completeNetworkSetup() error {
 	if err := c.syncContainer(); err != nil {
 		return err
 	}
-	if c.config.NetMode.IsSlirp4netns() {
+	if rootless.IsRootless() {
 		return c.runtime.setupRootlessNetNS(c)
+	} else if c.config.NetMode.IsSlirp4netns() {
+		return c.runtime.setupSlirp4netns(c)
 	}
 	if err := c.runtime.setupNetNS(c); err != nil {
 		return err