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, 9 insertions, 4 deletions

diff --git a/pkg/network/files.go b/pkg/network/files.go
index 38ce38b97..a2090491f 100644
--- a/pkg/network/files.go
+++ b/pkg/network/files.go
@@ -14,11 +14,16 @@ import (
 	"github.com/pkg/errors"
 )
 
-func GetCNIConfDir(config *config.Config) string {
-	if len(config.Network.NetworkConfigDir) < 1 {
-		return CNIConfigDir
+func GetCNIConfDir(configArg *config.Config) string {
+	if len(configArg.Network.NetworkConfigDir) < 1 {
+		dc, err := config.DefaultConfig()
+		if err != nil {
+			// Fallback to hard-coded dir
+			return CNIConfigDir
+		}
+		return dc.Network.NetworkConfigDir
 	}
-	return config.Network.NetworkConfigDir
+	return configArg.Network.NetworkConfigDir
 }
 
 // LoadCNIConfsFromDir loads all the CNI configurations from a dir