Merge pull request #2339 from phyber/iptables-check

controller: Check if IPTables is enabled for arrangeUserFilterRule

libnetwork/firewall_linux.go

@@ -2,6 +2,7 @@ package libnetwork
 
 import (
 	"github.com/docker/libnetwork/iptables"
+	"github.com/docker/libnetwork/netlabel"
 	"github.com/sirupsen/logrus"
 )
 
@@ -9,15 +10,44 @@ const userChain = "DOCKER-USER"
 
 func (c *controller) arrangeUserFilterRule() {
 	c.Lock()
-	arrangeUserFilterRule()
+
+	if c.hasIPTablesEnabled() {
+		arrangeUserFilterRule()
+	}
+
 	c.Unlock()
+
 	iptables.OnReloaded(func() {
 		c.Lock()
-		arrangeUserFilterRule()
+
+		if c.hasIPTablesEnabled() {
+			arrangeUserFilterRule()
+		}
+
 		c.Unlock()
 	})
 }
 
+func (c *controller) hasIPTablesEnabled() bool {
+	// Locking c should be handled in the calling method.
+	if c.cfg == nil || c.cfg.Daemon.DriverCfg[netlabel.GenericData] == nil {
+		return false
+	}
+
+	genericData, ok := c.cfg.Daemon.DriverCfg[netlabel.GenericData]
+	if !ok {
+		return false
+	}
+
+	optMap := genericData.(map[string]interface{})
+	enabled, ok := optMap["EnableIPTables"].(bool)
+	if !ok {
+		return false
+	}
+
+	return enabled
+}
+
 // This chain allow users to configure firewall policies in a way that persists
 // docker operations/restarts. Docker will not delete or modify any pre-existing
 // rules from the DOCKER-USER filter chain.