slirp4netns: add stub features and detection for disabled driver

Signed-off-by: fahed dorgaa <[email protected]>

Author: fahedouch

pkg/network/slirp4netns/slirp4netns_disabled.go

@@ -14,6 +14,33 @@ import (
 	"github.com/rootless-containers/rootlesskit/v3/pkg/network"
 )
 
+// Features is defined to satisfy references from cmd when the slirp4netns
+// network driver is disabled via the no_slirp4netns build tag.
+// It mirrors the shape of the real Features struct.
+type Features struct {
+	// SupportsEnableIPv6 --enable-ipv6 (v0.2.0)
+	SupportsEnableIPv6 bool
+	// SupportsCIDR --cidr (v0.3.0)
+	SupportsCIDR bool
+	// SupportsDisableHostLoopback --disable-host-loopback (v0.3.0)
+	SupportsDisableHostLoopback bool
+	// SupportsAPISocket --api-socket (v0.3.0)
+	SupportsAPISocket bool
+	// SupportsEnableSandbox --enable-sandbox (v0.4.0)
+	SupportsEnableSandbox bool
+	// SupportsEnableSeccomp --enable-seccomp (v0.4.0)
+	SupportsEnableSeccomp bool
+	// KernelSupportsEnableSeccomp whether the kernel supports slirp4netns --enable-seccomp
+	KernelSupportsEnableSeccomp bool
+}
+
+// DetectFeatures is a stub used when the slirp4netns network driver is
+// disabled via the no_slirp4netns build tag. It always returns an error so
+// callers can gracefully handle the lack of support at runtime.
+func DetectFeatures(binary string) (*Features, error) {
+	return nil, errors.New("slirp4netns network driver disabled by build tag no_slirp4netns")
+}
+
 // NewParentDriver returns a stub when built with the no_slirp4netns tag.
 func NewParentDriver(logWriter io.Writer, binary string, mtu int, ipnet *net.IPNet, ifname string, disableHostLoopback bool, apiSocketPath string, enableSandbox bool, enableSeccomp bool, enableIPv6 bool) (network.ParentDriver, error) {
 	return &disabledParent{}, errors.New("slirp4netns network driver disabled by build tag no_slirp4netns")