chore!(firewall): iptables logger level is set at FIREWALL_IPTABLES_LOG_LEVEL

- firewall log level is still fully controlled by `LOG_LEVEL`
- iptables log level defaults to `info` even if global log level is `debug` to minimize the amount of debug logs
- iptables log level is only set to debug if retro-compatible `FIREWALL_DEBUG=on` or if `FIREWALL_IPTABLES_LOG_LEVEL=debug`

internal/configuration/settings/firewall.go

@@ -15,7 +15,7 @@ type Firewall struct {
 	InputPorts      []uint16
 	OutboundSubnets []netip.Prefix
 	Enabled         *bool
-	Debug           *bool
+	Iptables        Iptables
 }
 
 func (f Firewall) validate() (err error) {
@@ -33,6 +33,11 @@ func (f Firewall) validate() (err error) {
 		}
 	}
 
+	err = f.Iptables.validate()
+	if err != nil {
+		return fmt.Errorf("iptables settings: %w", err)
+	}
+
 	return nil
 }
 
@@ -51,7 +56,7 @@ func (f *Firewall) copy() (copied Firewall) {
 		InputPorts:      gosettings.CopySlice(f.InputPorts),
 		OutboundSubnets: gosettings.CopySlice(f.OutboundSubnets),
 		Enabled:         gosettings.CopyPointer(f.Enabled),
-		Debug:           gosettings.CopyPointer(f.Debug),
+		Iptables:        f.Iptables.copy(),
 	}
 }
 
@@ -63,12 +68,12 @@ func (f *Firewall) overrideWith(other Firewall) {
 	f.InputPorts = gosettings.OverrideWithSlice(f.InputPorts, other.InputPorts)
 	f.OutboundSubnets = gosettings.OverrideWithSlice(f.OutboundSubnets, other.OutboundSubnets)
 	f.Enabled = gosettings.OverrideWithPointer(f.Enabled, other.Enabled)
-	f.Debug = gosettings.OverrideWithPointer(f.Debug, other.Debug)
+	f.Iptables.overrideWith(other.Iptables)
 }
 
-func (f *Firewall) setDefaults() {
+func (f *Firewall) setDefaults(globalLogLevel string) {
 	f.Enabled = gosettings.DefaultPointer(f.Enabled, true)
-	f.Debug = gosettings.DefaultPointer(f.Debug, false)
+	f.Iptables.setDefaults(globalLogLevel)
 }
 
 func (f Firewall) String() string {
@@ -83,9 +88,7 @@ func (f Firewall) toLinesNode() (node *gotree.Node) {
 		return node
 	}
 
-	if *f.Debug {
-		node.Appendf("Debug mode: on")
-	}
+	node.AppendNode(f.Iptables.toLinesNode())
 
 	if len(f.VPNInputPorts) > 0 {
 		vpnInputPortsNode := node.Appendf("VPN input ports:")
@@ -133,9 +136,9 @@ func (f *Firewall) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	f.Debug, err = r.BoolPtr("FIREWALL_DEBUG")
+	err = f.Iptables.read(r)
 	if err != nil {
-		return err
+		return fmt.Errorf("reading iptables settings: %w", err)
 	}
 
 	return nil

internal/configuration/settings/firewall_test.go

@@ -4,6 +4,7 @@ import (
 	"net/netip"
 	"testing"
 
+	"github.com/qdm12/log"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -15,7 +16,10 @@ func Test_Firewall_validate(t *testing.T) {
 		errWrapped error
 		errMessage string
 	}{
-		"empty": {},
+		"empty": {
+			errWrapped: log.ErrLevelNotRecognized,
+			errMessage: "iptables settings: log level: level is not recognized: ",
+		},
 		"zero_vpn_input_port": {
 			firewall: Firewall{
 				VPNInputPorts: []uint16{0},
@@ -41,6 +45,7 @@ func Test_Firewall_validate(t *testing.T) {
 		},
 		"public_outbound_subnet": {
 			firewall: Firewall{
+				Iptables: Iptables{LogLevel: log.LevelInfo.String()},
 				OutboundSubnets: []netip.Prefix{
 					netip.MustParsePrefix("1.2.3.4/32"),
 				},
@@ -48,6 +53,7 @@ func Test_Firewall_validate(t *testing.T) {
 		},
 		"valid_settings": {
 			firewall: Firewall{
+				Iptables:      Iptables{LogLevel: log.LevelInfo.String()},
 				VPNInputPorts: []uint16{100, 101},
 				InputPorts:    []uint16{200, 201},
 				OutboundSubnets: []netip.Prefix{

internal/configuration/settings/iptables.go

@@ -0,0 +1,67 @@
+package settings
+
+import (
+	"fmt"
+
+	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gosettings/reader"
+	"github.com/qdm12/gotree"
+	"github.com/qdm12/log"
+)
+
+// Iptables contains settings to customize iptables.
+type Iptables struct {
+	LogLevel string
+}
+
+func (i Iptables) validate() (err error) {
+	_, err = log.ParseLevel(i.LogLevel)
+	if err != nil {
+		return fmt.Errorf("log level: %w", err)
+	}
+
+	return nil
+}
+
+func (i *Iptables) copy() (copied Iptables) {
+	return Iptables{
+		LogLevel: i.LogLevel,
+	}
+}
+
+func (i *Iptables) overrideWith(other Iptables) {
+	i.LogLevel = gosettings.OverrideWithComparable(i.LogLevel, other.LogLevel)
+}
+
+func (i *Iptables) setDefaults(globalLogLevel string) {
+	defaultLevel := globalLogLevel
+	if defaultLevel == log.LevelDebug.String() {
+		// Given iptables debug logger is quite verbose, we only turn it to debug level
+		// if it is explicitly asked to be at debug level; even if the global logger is
+		// at the debug level, we keep iptables at info level by default.
+		defaultLevel = log.LevelInfo.String()
+	}
+	i.LogLevel = gosettings.DefaultComparable(i.LogLevel, defaultLevel)
+}
+
+func (i Iptables) String() string {
+	return i.toLinesNode().String()
+}
+
+func (i Iptables) toLinesNode() (node *gotree.Node) {
+	node = gotree.New("Iptables settings:")
+	node.Appendf("Log level: %s", i.LogLevel)
+	return node
+}
+
+func (i *Iptables) read(r *reader.Reader) (err error) {
+	debugMode, err := r.BoolPtr("FIREWALL_DEBUG", reader.IsRetro("FIREWALL_IPTABLES_LOG_LEVEL"))
+	if err != nil {
+		return err
+	}
+	if debugMode != nil && *debugMode {
+		i.LogLevel = log.LevelDebug.String()
+	}
+	i.LogLevel = r.String("FIREWALL_IPTABLES_LOG_LEVEL")
+	return nil
+}

internal/configuration/settings/settings.go

@@ -120,10 +120,10 @@ func (s *Settings) OverrideWith(other Settings,
 func (s *Settings) SetDefaults() {
 	s.ControlServer.setDefaults()
 	s.DNS.setDefaults()
-	s.Firewall.setDefaults()
+	s.Log.setDefaults()
+	s.Firewall.setDefaults(s.Log.Level)
 	s.Health.SetDefaults()
 	s.HTTPProxy.setDefaults()
-	s.Log.setDefaults()
 	s.PublicIP.setDefaults()
 	s.Shadowsocks.setDefaults()
 	s.Storage.setDefaults()

internal/configuration/settings/settings_test.go

@@ -62,7 +62,9 @@ func Test_Settings_String(t *testing.T) {
 |       ├── Block ads: no
 |       └── Block surveillance: yes
 ├── Firewall settings:
-|   └── Enabled: yes
+|   ├── Enabled: yes
+|   └── Iptables settings:
+|       └── Log level: INFO
 ├── Log settings:
 |   └── Log level: INFO
 ├── Health settings: