libnetwork/config: add Config.DriverConfig() and un-export DriverCfg

The driver-configurations are only set when creating a new controller,
using the `config.OptionDriverConfig()` option that can be passed to
`New()`, and used as "read-only" after that.

Taking away any other paths that set these options, the only type used
for per-driver options are a `map[string]interface{}`, so we can change
the type from `map[string]interface{}` to a `map[string]map[string]interface{}`,
(or its "modern" variant: `map[string]map[string]any`), so that it's
no longer needed to cast the type before use.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

libnetwork/config/config.go

@@ -25,7 +25,7 @@ type Config struct {
 	DefaultNetwork         string
 	DefaultDriver          string
 	Labels                 []string
-	DriverCfg              map[string]interface{}
+	driverCfg              map[string]map[string]any
 	ClusterProvider        cluster.Provider
 	NetworkControlPlaneMTU int
 	DefaultAddressPool     []*ipamutils.NetworkToSplit
@@ -37,7 +37,7 @@ type Config struct {
 // New creates a new Config and initializes it with the given Options.
 func New(opts ...Option) *Config {
 	cfg := &Config{
-		DriverCfg: make(map[string]interface{}),
+		driverCfg: make(map[string]map[string]any),
 	}
 
 	for _, opt := range opts {
@@ -53,6 +53,10 @@ func New(opts ...Option) *Config {
 	return cfg
 }
 
+func (c *Config) DriverConfig(name string) map[string]any {
+	return c.driverCfg[name]
+}
+
 // Option is an option setter function type used to pass various configurations
 // to the controller
 type Option func(c *Config)
@@ -81,9 +85,9 @@ func OptionDefaultAddressPoolConfig(addressPool []*ipamutils.NetworkToSplit) Opt
 }
 
 // OptionDriverConfig returns an option setter for driver configuration.
-func OptionDriverConfig(networkType string, config map[string]interface{}) Option {
+func OptionDriverConfig(networkType string, config map[string]any) Option {
 	return func(c *Config) {
-		c.DriverCfg[networkType] = config
+		c.driverCfg[networkType] = config
 	}
 }
 

libnetwork/controller.go

@@ -335,11 +335,9 @@ func (c *Controller) makeDriverConfig(ntype string) map[string]interface{} {
 		cfg[key] = val
 	}
 
-	drvCfg, ok := c.cfg.DriverCfg[ntype]
-	if ok {
-		for k, v := range drvCfg.(map[string]interface{}) {
-			cfg[k] = v
-		}
+	// Merge in the existing config for this driver.
+	for k, v := range c.cfg.DriverConfig(ntype) {
+		cfg[k] = v
 	}
 
 	if c.cfg.Scope.IsValid() {
@@ -1146,10 +1144,7 @@ func (c *Controller) iptablesEnabled() bool {
 		return false
 	}
 	// parse map cfg["bridge"]["generic"]["EnableIPTable"]
-	cfgBridge, ok := c.cfg.DriverCfg["bridge"].(map[string]interface{})
-	if !ok {
-		return false
-	}
+	cfgBridge := c.cfg.DriverConfig("bridge")
 	cfgGeneric, ok := cfgBridge[netlabel.GenericData].(options.Generic)
 	if !ok {
 		return false
@@ -1170,10 +1165,7 @@ func (c *Controller) ip6tablesEnabled() bool {
 		return false
 	}
 	// parse map cfg["bridge"]["generic"]["EnableIP6Table"]
-	cfgBridge, ok := c.cfg.DriverCfg["bridge"].(map[string]interface{})
-	if !ok {
-		return false
-	}
+	cfgBridge := c.cfg.DriverConfig("bridge")
 	cfgGeneric, ok := cfgBridge[netlabel.GenericData].(options.Generic)
 	if !ok {
 		return false