libpod: Move rootless network setup details to container_internal_linux.go

This removes a use of state.NetNS which is a linux-specific field defined
in container_linux.go from the generic container_internal.go, allowing
that to build on non-linux platforms.

[NO NEW TESTS NEEDED]

Signed-off-by: Doug Rabson <dfr@rabson.org>

libpod/container_internal.go

@@ -293,20 +293,8 @@ func (c *Container) handleRestartPolicy(ctx context.Context) (_ bool, retErr err
 	}
 
 	// set up slirp4netns again because slirp4netns will die when conmon exits
-	if c.config.NetMode.IsSlirp4netns() {
+	if err := c.setupRootlessNetwork(); err != nil {
-		err := c.runtime.setupSlirp4netns(c, c.state.NetNS)
+		return false, err
-		if err != nil {
-			return false, err
-		}
-	}
-
-	// set up rootlesskit port forwarder again since it dies when conmon exits
-	// we use rootlesskit port forwarder only as rootless and when bridge network is used
-	if rootless.IsRootless() && c.config.NetMode.IsBridge() && len(c.config.PortMappings) > 0 {
-		err := c.runtime.setupRootlessPortMappingViaRLK(c, c.state.NetNS.Path(), c.state.NetworkStatus)
-		if err != nil {
-			return false, err
-		}
 	}
 
 	if c.state.State == define.ContainerStateStopped {

libpod/container_internal_linux.go

@@ -3228,3 +3228,24 @@ func (c *Container) ChangeHostPathOwnership(src string, recurse bool, uid, gid i
 	}
 	return chown.ChangeHostPathOwnership(src, recurse, uid, gid)
 }
+
+// If the container is rootless, set up the slirp4netns network
+func (c *Container) setupRootlessNetwork() error {
+	// set up slirp4netns again because slirp4netns will die when conmon exits
+	if c.config.NetMode.IsSlirp4netns() {
+		err := c.runtime.setupSlirp4netns(c, c.state.NetNS)
+		if err != nil {
+			return err
+		}
+	}
+
+	// set up rootlesskit port forwarder again since it dies when conmon exits
+	// we use rootlesskit port forwarder only as rootless and when bridge network is used
+	if rootless.IsRootless() && c.config.NetMode.IsBridge() && len(c.config.PortMappings) > 0 {
+		err := c.runtime.setupRootlessPortMappingViaRLK(c, c.state.NetNS.Path(), c.state.NetworkStatus)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}