podman network reload add rootless support

Allow podman network reload to be run as rootless user. While it is
unlikely that the iptable rules are flushed inside the rootless cni
namespace, it could still happen. Also fix podman network reload --all
to ignore errors when a container does not have the bridge network mode,
e.g. slirp4netns.

Signed-off-by: Paul Holzinger <paul.holzinger@web.de>

libpod/define/errors.go

@@ -179,6 +179,9 @@ var (
 	// ErrNoNetwork indicates that a container has no net namespace, like network=none
 	ErrNoNetwork = errors.New("container has no network namespace")
 
+	// ErrNetworkModeInvalid indicates that a container has the wrong network mode for an operation
+	ErrNetworkModeInvalid = errors.New("invalid network mode")
+
 	// ErrSetSecurityAttribute indicates that a request to set a container's security attribute
 	// was not possible.
 	ErrSetSecurityAttribute = fmt.Errorf("%w: unable to assign security attribute", ErrOCIRuntime)

libpod/networking_linux.go

@@ -23,6 +23,7 @@ import (
 	"github.com/containers/podman/v3/libpod/events"
 	"github.com/containers/podman/v3/libpod/network"
 	"github.com/containers/podman/v3/pkg/errorhandling"
+	"github.com/containers/podman/v3/pkg/namespaces"
 	"github.com/containers/podman/v3/pkg/netns"
 	"github.com/containers/podman/v3/pkg/resolvconf"
 	"github.com/containers/podman/v3/pkg/rootless"
@@ -757,6 +758,15 @@ func getContainerNetNS(ctr *Container) (string, error) {
 	return "", nil
 }
 
+// isBridgeNetMode checks if the given network mode is bridge.
+// It returns nil when it is set to bridge and an error otherwise.
+func isBridgeNetMode(n namespaces.NetworkMode) error {
+	if !n.IsBridge() {
+		return errors.Wrapf(define.ErrNetworkModeInvalid, "%q is not supported", n)
+	}
+	return nil
+}
+
 // Reload only works with containers with a configured network.
 // It will tear down, and then reconfigure, the network of the container.
 // This is mainly used when a reload of firewall rules wipes out existing
@@ -770,8 +780,8 @@ func (r *Runtime) reloadContainerNetwork(ctr *Container) ([]*cnitypes.Result, er
 	if ctr.state.NetNS == nil {
 		return nil, errors.Wrapf(define.ErrCtrStateInvalid, "container %s network is not configured, refusing to reload", ctr.ID())
 	}
-	if rootless.IsRootless() || ctr.config.NetMode.IsSlirp4netns() {
-		return nil, errors.Wrapf(define.ErrRootless, "network reload only supported for root containers")
+	if err := isBridgeNetMode(ctr.config.NetMode); err != nil {
+		return nil, err
 	}
 
 	logrus.Infof("Going to reload container %s network", ctr.ID())
@@ -1025,8 +1035,8 @@ func (w *logrusDebugWriter) Write(p []byte) (int, error) {
 // NetworkDisconnect removes a container from the network
 func (c *Container) NetworkDisconnect(nameOrID, netName string, force bool) error {
 	// only the bridge mode supports cni networks
-	if !c.config.NetMode.IsBridge() {
-		return errors.Errorf("network mode %q is not supported", c.config.NetMode)
+	if err := isBridgeNetMode(c.config.NetMode); err != nil {
+		return err
 	}
 
 	networks, err := c.networksByNameIndex()
@@ -1086,8 +1096,8 @@ func (c *Container) NetworkDisconnect(nameOrID, netName string, force bool) erro
 // ConnectNetwork connects a container to a given network
 func (c *Container) NetworkConnect(nameOrID, netName string, aliases []string) error {
 	// only the bridge mode supports cni networks
-	if !c.config.NetMode.IsBridge() {
-		return errors.Errorf("network mode %q is not supported", c.config.NetMode)
+	if err := isBridgeNetMode(c.config.NetMode); err != nil {
+		return err
 	}
 
 	networks, err := c.networksByNameIndex()