Add docker interfaces to firewalld docker zone

If firewalld is running, create a new docker zone and
add the docker interfaces to the docker zone to allow
container networking for distros with Firewalld enabled

Fixes: #2496

Signed-off-by: Arko Dasgupta <[email protected]>

iptables/firewalld.go

@@ -19,9 +19,12 @@ const (
 	// Ebtables point to bridge table
 	Ebtables IPV = "eb"
 )
+
+// Reference - https://firewalld.org/documentation/man-pages/firewalld.dbus.html
 const (
 	dbusInterface = "org.fedoraproject.FirewallD1"
 	dbusPath      = "/org/fedoraproject/FirewallD1"
+	dockerZone    = "docker"
 )
 
 // Conn is a connection to firewalld dbus endpoint.
@@ -51,6 +54,9 @@ func FirewalldInit() error {
 	}
 	if connection != nil {
 		go signalHandler()
+		if err := setupDockerZone(); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -165,3 +171,78 @@ func Passthrough(ipv IPV, args ...string) ([]byte, error) {
 	}
 	return []byte(output), nil
 }
+
+// setupDockerZone creates a zone called docker in firewalld which includes docker interfaces to allow
+// container networking
+func setupDockerZone() error {
+	var zones []string
+	// Check if zone exists
+	if err := connection.sysobj.Call(dbusInterface+".zone.getZones", 0).Store(&zones); err != nil {
+		return err
+	}
+	if contains(zones, dockerZone) {
+		logrus.Infof("Firewalld: %s zone already exists, returning", dockerZone)
+		return nil
+	}
+
+	logrus.Debugf("Firewalld: creating %s zone", dockerZone)
+	var output string
+	settings := "version='1.0',target='ACCEPT'"
+	// Permanent
+	if err := connection.sysobj.Call(dbusInterface+".config.addZone", 0, dockerZone, settings).Store(&output); err != nil {
+		return err
+	}
+	return nil
+}
+
+// AddInterfaceFirewalld adds the interface to the trusted zone
+func AddInterfaceFirewalld(intf string) error {
+	var intfs []string
+	// Check if interface is already added to the zone
+	if err := connection.sysobj.Call(dbusInterface+".zone.getInterfaces", 0, dockerZone).Store(&intfs); err != nil {
+		return err
+	}
+	// Return if interface is already part of the zone
+	if contains(intfs, intf) {
+		logrus.Infof("Firewalld: interface %s already part of %s zone, returning", intf, dockerZone)
+		return nil
+	}
+
+	logrus.Debugf("Firewalld: adding %s interface to %s zone", intf, dockerZone)
+	var output string
+	// Runtime
+	if err := connection.sysobj.Call(dbusInterface+".zone.addInterface", 0, dockerZone, intf).Store(&output); err != nil {
+		return err
+	}
+	return nil
+}
+
+// DelInterfaceFirewalld removes the interface from the trusted zone
+func DelInterfaceFirewalld(intf string) error {
+	var intfs []string
+	// Check if interface is part of the zone
+	if err := connection.sysobj.Call(dbusInterface+".zone.getInterfaces", 0, dockerZone).Store(&intfs); err != nil {
+		return err
+	}
+	// Remove interface if it exists
+	if !contains(intfs, intf) {
+		return fmt.Errorf("Firewalld: unable to find interface %s in %s zone", intf, dockerZone)
+	}
+
+	logrus.Debugf("Firewalld: removing %s interface from %s zone", intf, dockerZone)
+	var output string
+	// Runtime
+	if err := connection.sysobj.Call(dbusInterface+".zone.removeInterface", 0, dockerZone, intf).Store(&output); err != nil {
+		return err
+	}
+	return nil
+}
+
+func contains(list []string, val string) bool {
+	for _, v := range list {
+		if v == val {
+			return true
+		}
+	}
+	return false
+}

iptables/iptables.go

@@ -146,6 +146,19 @@ func ProgramChain(c *ChainInfo, bridgeName string, hairpinMode, enable bool) err
 		return errors.New("Could not program chain, missing chain name")
 	}
 
+	// Either add or remove the interface from the firewalld zone
+	if firewalldRunning {
+		if enable {
+			if err := AddInterfaceFirewalld(bridgeName); err != nil {
+				return err
+			}
+		} else {
+			if err := DelInterfaceFirewalld(bridgeName); err != nil {
+				return err
+			}
+		}
+	}
+
 	switch c.Table {
 	case Nat:
 		preroute := []string{