fw: allow to configure interception queue number

- Added new configuration field to allow configure fw interception
   number queue (default to 0):
   "FwOptions": {
      "QueueNum": 0
   }
   (we still need to reconfigure nfqueue queues in order for this to
take effect).
 - If the fw configuration path is not supplied, default to
   /etc/opensnitchd/system-fw.json

daemon/firewall/common/common.go

@@ -84,14 +84,10 @@ func (c *Common) SetRulesCheckerInterval(interval string) {
 
 // SetQueueNum sets the queue number used by the firewall.
 // It's the queue where all intercepted connections will be sent.
-func (c *Common) SetQueueNum(qNum *int) {
+func (c *Common) SetQueueNum(qNum uint16) {
 	c.Lock()
 	defer c.Unlock()
-
-	if qNum != nil {
-		c.QueueNum = uint16(*qNum)
-	}
-
+	c.QueueNum = qNum
 }
 
 // IsRunning returns if the firewall is running or not.

daemon/firewall/config/config.go

@@ -18,6 +18,11 @@ import (
 	"github.com/fsnotify/fsnotify"
 )
 
+var (
+	// DefaultConfigFile ..
+	DefaultConfigFile = "/etc/opensnitchd/system-fw.json"
+)
+
 // ExprValues holds the statements' options:
 // "Name": "ct",
 // "Values": [

daemon/firewall/iptables/iptables.go

@@ -93,7 +93,7 @@ func (ipt *Iptables) Name() string {
 
 // Init inserts the firewall rules and starts monitoring for firewall
 // changes.
-func (ipt *Iptables) Init(qNum *int, configPath, monitorInterval string) {
+func (ipt *Iptables) Init(qNum uint16, configPath, monitorInterval string) {
 	if ipt.IsRunning() {
 		return
 	}

daemon/firewall/nftables/nftables.go

@@ -71,7 +71,7 @@ func (n *Nft) Name() string {
 
 // Init inserts the firewall rules and starts monitoring for firewall
 // changes.
-func (n *Nft) Init(qNum *int, configPath, monitorInterval string) {
+func (n *Nft) Init(qNum uint16, configPath, monitorInterval string) {
 	if n.IsRunning() {
 		return
 	}

daemon/firewall/rules.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"github.com/evilsocket/opensnitch/daemon/firewall/common"
+	"github.com/evilsocket/opensnitch/daemon/firewall/config"
 	"github.com/evilsocket/opensnitch/daemon/firewall/iptables"
 	"github.com/evilsocket/opensnitch/daemon/firewall/nftables"
 	"github.com/evilsocket/opensnitch/daemon/log"
@@ -12,11 +13,11 @@ import (
 
 // Firewall is the interface that all firewalls (iptables, nftables) must implement.
 type Firewall interface {
-	Init(*int, string, string)
+	Init(uint16, string, string)
 	Stop()
 	Name() string
 	IsRunning() bool
-	SetQueueNum(num *int)
+	SetQueueNum(num uint16)
 
 	SaveConfiguration(rawConfig string) error
 
@@ -37,19 +38,15 @@ type Firewall interface {
 }
 
 var (
-	fw            Firewall
-	queueNum      = 0
-	DefaultConfig = "/etc/opensnitchd/system-fw.json"
+	fw       Firewall
+	queueNum = uint16(0)
 )
 
 // Init initializes the firewall and loads firewall rules.
 // We'll try to use the firewall configured in the configuration (iptables/nftables).
 // If iptables is not installed, we can add nftables rules directly to the kernel,
 // without relying on any binaries.
-func Init(fwType, configPath, monitorInterval string, qNum *int) (err error) {
-	if configPath == "" {
-		configPath = DefaultConfig
-	}
+func Init(fwType, configPath, monitorInterval string, qNum uint16) (err error) {
 	if fwType == iptables.Name {
 		fw, err = iptables.Fw()
 		if err != nil {
@@ -71,9 +68,12 @@ func Init(fwType, configPath, monitorInterval string, qNum *int) (err error) {
 	if fw == nil {
 		return fmt.Errorf("Firewall not initialized")
 	}
+	if configPath == "" {
+		configPath = config.DefaultConfigFile
+	}
 	fw.Stop()
 	fw.Init(qNum, configPath, monitorInterval)
-	queueNum = *qNum
+	queueNum = qNum
 
 	log.Info("Using %s firewall", fw.Name())
 
@@ -104,9 +104,9 @@ func CleanRules(logErrors bool) {
 }
 
 // Reload stops current firewall and initializes a new one.
-func Reload(fwtype, configPath, monitorInterval string) (err error) {
+func Reload(fwtype, configPath, monitorInterval string, queueNum uint16) (err error) {
 	Stop()
-	err = Init(fwtype, configPath, monitorInterval, &queueNum)
+	err = Init(fwtype, configPath, monitorInterval, queueNum)
 	return
 }
 

daemon/main.go

@@ -151,19 +151,19 @@ func overwriteLogging() bool {
 	return debug || warning || important || errorlog || logFile != "" || logMicro
 }
 
-func setupQueues() {
+func setupQueues(qNum uint16) {
 	// prepare the queue
 	var err error
-	queue, err = netfilter.NewQueue(uint16(queueNum))
+	queue, err = netfilter.NewQueue(qNum)
 	if err != nil {
-		msg := fmt.Sprintf("Error creating queue #%d: %s", queueNum, err)
+		msg := fmt.Sprintf("Error creating queue #%d: %s", qNum, err)
 		uiClient.SendWarningAlert(msg)
 		log.Warning("Is opensnitchd already running?")
 		log.Fatal(msg)
 	}
 	pktChan = queue.Packets()
 
-	repeatQueueNum = queueNum + 1
+	repeatQueueNum = int(qNum) + 1
 
 	repeatQueue, err = netfilter.NewQueue(uint16(repeatQueueNum))
 	if err != nil {
@@ -173,6 +173,7 @@ func setupQueues() {
 		log.Warning(msg)
 	}
 	repeatPktChan = repeatQueue.Packets()
+	log.Info("Listening on queue number %d ...", qNum)
 }
 
 func setupLogging() {
@@ -581,6 +582,10 @@ func main() {
 	}
 	log.Info("Using system fw configuration %s ...", fwConfigFile)
 
+	if uint16(queueNum) != cfg.FwOptions.QueueNum && queueNum > 0 {
+		cfg.FwOptions.QueueNum = uint16(queueNum)
+	}
+
 	setupSignals()
 
 	log.Info("Loading rules from %s ...", rulesPath)
@@ -596,7 +601,7 @@ func main() {
 	uiClient = ui.NewClient(uiSocket, configFile, stats, rules, loggerMgr)
 
 	setupWorkers()
-	setupQueues()
+	setupQueues(cfg.FwOptions.QueueNum)
 
 	// queue and firewall rules should be ready by now
 

daemon/ui/config/config.go

@@ -58,6 +58,7 @@ type (
 		ConfigPath      string `json:"ConfigPath"`
 		BypassQueue     string `json:"BypassQueue"`
 		MonitorInterval string `json:"MonitorInterval"`
+		QueueNum        uint16 `json:"QueueNum"`
 	}
 
 	// EbpfOptions struct

daemon/ui/config_utils.go

@@ -167,6 +167,7 @@ func (c *Client) reloadConfiguration(reload bool, newConfig config.Config) *moni
 
 	if c.GetFirewallType() != newConfig.Firewall ||
 		newConfig.FwOptions.ConfigPath != c.config.FwOptions.ConfigPath ||
+		newConfig.FwOptions.QueueNum != c.config.FwOptions.QueueNum ||
 		newConfig.FwOptions.MonitorInterval != c.config.FwOptions.MonitorInterval {
 		log.Debug("[config] reloading config.firewall")
 
@@ -174,6 +175,7 @@ func (c *Client) reloadConfiguration(reload bool, newConfig config.Config) *moni
 			newConfig.Firewall,
 			newConfig.FwOptions.ConfigPath,
 			newConfig.FwOptions.MonitorInterval,
+			newConfig.FwOptions.QueueNum,
 		)
 	} else {
 		log.Debug("[config] config.firewall not changed")