chore(firewall): split apart iptables specific code in internal/firewall/iptables

cmd/gluetun/main.go

@@ -283,7 +283,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	err = printVersions(ctx, logger, []printVersionElement{
 		{name: "Alpine", getVersion: alpineConf.Version},
 		{name: "OpenVPN", getVersion: ovpnVersion},
-		{name: "IPtables", getVersion: firewallConf.Version},
+		{name: "Firewall", getVersion: firewallConf.Version},
 	})
 	if err != nil {
 		return err

internal/firewall/enable.go

@@ -42,13 +42,13 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 }
 
 func (c *Config) disable(ctx context.Context) (err error) {
-	if err = c.clearAllRules(ctx); err != nil {
+	if err = c.impl.ClearAllRules(ctx); err != nil {
 		return fmt.Errorf("clearing all rules: %w", err)
 	}
-	if err = c.setIPv4AllPolicies(ctx, "ACCEPT"); err != nil {
+	if err = c.impl.SetIPv4AllPolicies(ctx, "ACCEPT"); err != nil {
 		return fmt.Errorf("setting ipv4 policies: %w", err)
 	}
-	if err = c.setIPv6AllPolicies(ctx, "ACCEPT"); err != nil {
+	if err = c.impl.SetIPv6AllPolicies(ctx, "ACCEPT"); err != nil {
 		return fmt.Errorf("setting ipv6 policies: %w", err)
 	}
 
@@ -72,33 +72,31 @@ func (c *Config) fallbackToDisabled(ctx context.Context) {
 }
 
 func (c *Config) enable(ctx context.Context) (err error) {
-	touched := false
-	if err = c.setIPv4AllPolicies(ctx, "DROP"); err != nil {
-		return err
-	}
-	touched = true
-
-	if err = c.setIPv6AllPolicies(ctx, "DROP"); err != nil {
+	if err = c.impl.SetIPv4AllPolicies(ctx, "DROP"); err != nil {
 		return err
 	}
 
-	const remove = false
+	if err = c.impl.SetIPv6AllPolicies(ctx, "DROP"); err != nil {
+		return err
+	}
 
 	defer func() {
-		if touched && err != nil {
+		if err != nil {
 			c.fallbackToDisabled(ctx)
 		}
 	}()
 
+	const remove = false
+
 	// Loopback traffic
-	if err = c.acceptInputThroughInterface(ctx, "lo", remove); err != nil {
+	if err = c.impl.AcceptInputThroughInterface(ctx, "lo", remove); err != nil {
 		return err
 	}
-	if err = c.acceptOutputThroughInterface(ctx, "lo", remove); err != nil {
+	if err = c.impl.AcceptOutputThroughInterface(ctx, "lo", remove); err != nil {
 		return err
 	}
 
-	if err = c.acceptEstablishedRelatedTraffic(ctx, remove); err != nil {
+	if err = c.impl.AcceptEstablishedRelatedTraffic(ctx, remove); err != nil {
 		return err
 	}
 
@@ -108,7 +106,9 @@ func (c *Config) enable(ctx context.Context) (err error) {
 
 	localInterfaces := make(map[string]struct{}, len(c.localNetworks))
 	for _, network := range c.localNetworks {
-		if err := c.acceptOutputFromIPToSubnet(ctx, network.InterfaceName, network.IP, network.IPNet, remove); err != nil {
+		err = c.impl.AcceptOutputFromIPToSubnet(ctx,
+			network.InterfaceName, network.IP, network.IPNet, remove)
+		if err != nil {
 			return err
 		}
 
@@ -117,7 +117,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 			continue
 		}
 		localInterfaces[network.InterfaceName] = struct{}{}
-		err = c.acceptIpv6MulticastOutput(ctx, network.InterfaceName, remove)
+		err = c.impl.AcceptIpv6MulticastOutput(ctx, network.InterfaceName, remove)
 		if err != nil {
 			return fmt.Errorf("accepting IPv6 multicast output: %w", err)
 		}
@@ -130,7 +130,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 	// Allows packets from any IP address to go through eth0 / local network
 	// to reach Gluetun.
 	for _, network := range c.localNetworks {
-		if err := c.acceptInputToSubnet(ctx, network.InterfaceName, network.IPNet, remove); err != nil {
+		if err := c.impl.AcceptInputToSubnet(ctx, network.InterfaceName, network.IPNet, remove); err != nil {
 			return err
 		}
 	}
@@ -144,7 +144,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 		return fmt.Errorf("redirecting ports: %w", err)
 	}
 
-	if err := c.runUserPostRules(ctx, c.customRulesPath, remove); err != nil {
+	if err := c.impl.RunUserPostRules(ctx, c.customRulesPath, remove); err != nil {
 		return fmt.Errorf("running user defined post firewall rules: %w", err)
 	}
 
@@ -164,7 +164,7 @@ func (c *Config) allowVPNIP(ctx context.Context) (err error) {
 			continue
 		}
 		interfacesSeen[defaultRoute.NetInterface] = struct{}{}
-		err = c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove)
+		err = c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove)
 		if err != nil {
 			return fmt.Errorf("accepting output traffic through VPN: %w", err)
 		}
@@ -186,7 +186,7 @@ func (c *Config) allowOutboundSubnets(ctx context.Context) (err error) {
 			firewallUpdated = true
 
 			const remove = false
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subnet, remove)
 			if err != nil {
 				return err
@@ -204,7 +204,7 @@ func (c *Config) allowInputPorts(ctx context.Context) (err error) {
 	for port, netInterfaces := range c.allowedInputPorts {
 		for netInterface := range netInterfaces {
 			const remove = false
-			err = c.acceptInputToPort(ctx, netInterface, port, remove)
+			err = c.impl.AcceptInputToPort(ctx, netInterface, port, remove)
 			if err != nil {
 				return fmt.Errorf("accepting input port %d on interface %s: %w",
 					port, netInterface, err)
@@ -216,7 +216,7 @@ func (c *Config) allowInputPorts(ctx context.Context) (err error) {
 
 func (c *Config) redirectPorts(ctx context.Context, remove bool) (err error) {
 	for _, portRedirection := range c.portRedirections {
-		err = c.redirectPort(ctx, portRedirection.interfaceName, portRedirection.sourcePort,
+		err = c.impl.RedirectPort(ctx, portRedirection.interfaceName, portRedirection.sourcePort,
 			portRedirection.destinationPort, remove)
 		if err != nil {
 			return err

internal/firewall/firewall.go

@@ -2,24 +2,23 @@ package firewall
 
 import (
 	"context"
+	"fmt"
 	"net/netip"
 	"sync"
 
+	"github.com/qdm12/gluetun/internal/firewall/iptables"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/routing"
 )
 
 type Config struct {
-	runner         CmdRunner
-	logger         Logger
-	iptablesMutex  sync.Mutex
-	ip6tablesMutex sync.Mutex
-	defaultRoutes  []routing.DefaultRoute
-	localNetworks  []routing.LocalNetwork
+	runner        CmdRunner
+	logger        Logger
+	defaultRoutes []routing.DefaultRoute
+	localNetworks []routing.LocalNetwork
 
-	// Fixed state
-	ipTables        string
-	ip6Tables       string
+	// Fixed
+	impl            firewallImpl
 	customRulesPath string
 
 	// State
@@ -38,25 +37,19 @@ func NewConfig(ctx context.Context, logger Logger,
 	runner CmdRunner, defaultRoutes []routing.DefaultRoute,
 	localNetworks []routing.LocalNetwork,
 ) (config *Config, err error) {
-	iptables, err := checkIptablesSupport(ctx, runner, "iptables", "iptables-nft", "iptables-legacy")
+	impl, err := iptables.New(ctx, runner, logger)
 	if err != nil {
-		return nil, err
-	}
-
-	ip6tables, err := findIP6tablesSupported(ctx, runner)
-	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("creating iptables firewall: %w", err)
 	}
 
 	return &Config{
 		runner:            runner,
 		logger:            logger,
 		allowedInputPorts: make(map[uint16]map[string]struct{}),
-		ipTables:          iptables,
-		ip6Tables:         ip6tables,
-		customRulesPath:   "/iptables/post-rules.txt",
 		// Obtained from routing
-		defaultRoutes: defaultRoutes,
-		localNetworks: localNetworks,
+		defaultRoutes:   defaultRoutes,
+		localNetworks:   localNetworks,
+		impl:            impl,
+		customRulesPath: "/iptables/post-rules.txt",
 	}, nil
 }

internal/firewall/interfaces.go

@@ -1,6 +1,12 @@
 package firewall
 
-import "os/exec"
+import (
+	"context"
+	"net/netip"
+	"os/exec"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
 
 type CmdRunner interface {
 	Run(cmd *exec.Cmd) (output string, err error)
@@ -12,3 +18,25 @@ type Logger interface {
 	Warn(s string)
 	Error(s string)
 }
+
+type firewallImpl interface { //nolint:interfacebloat
+	AcceptEstablishedRelatedTraffic(ctx context.Context, remove bool) error
+	AcceptInputThroughInterface(ctx context.Context, intf string, remove bool) error
+	AcceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error
+	AcceptInputToSubnet(ctx context.Context, intf string, subnet netip.Prefix, remove bool) error
+	AcceptIpv6MulticastOutput(ctx context.Context, intf string, remove bool) error
+	AcceptOutputFromIPToSubnet(ctx context.Context, intf string, assignedIP netip.Addr,
+		subnet netip.Prefix, remove bool) error
+	AcceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error
+	AcceptOutputTrafficToVPN(ctx context.Context, intf string,
+		connection models.Connection, remove bool) error
+	ClearAllRules(ctx context.Context) error
+	RedirectPort(ctx context.Context, intf string, sourcePort,
+		destinationPort uint16, remove bool) error
+	RunUserPostRules(ctx context.Context, customRulesPath string, remove bool) error
+	SetIPv4AllPolicies(ctx context.Context, policy string) error
+	SetIPv6AllPolicies(ctx context.Context, policy string) error
+	TempDropOutputTCPRST(ctx context.Context, src, dst netip.AddrPort, excludeMark int) (
+		revert func(ctx context.Context) error, err error)
+	Version(ctx context.Context) (version string, err error)
+}

internal/firewall/iptables/cmd_matcher_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"fmt"

internal/firewall/iptables/delete.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"

internal/firewall/iptables/delete_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"

internal/firewall/iptables/firewall.go

@@ -0,0 +1,36 @@
+package iptables
+
+import (
+	"context"
+	"sync"
+)
+
+type Config struct {
+	runner         CmdRunner
+	logger         Logger
+	iptablesMutex  sync.Mutex
+	ip6tablesMutex sync.Mutex
+
+	// Fixed state
+	ipTables  string
+	ip6Tables string
+}
+
+func New(ctx context.Context, runner CmdRunner, logger Logger) (*Config, error) {
+	iptables, err := checkIptablesSupport(ctx, runner, "iptables", "iptables-nft", "iptables-legacy")
+	if err != nil {
+		return nil, err
+	}
+
+	ip6tables, err := findIP6tablesSupported(ctx, runner)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Config{
+		runner:    runner,
+		logger:    logger,
+		ipTables:  iptables,
+		ip6Tables: ip6tables,
+	}, nil
+}

internal/firewall/iptables/interfaces.go

@@ -0,0 +1,14 @@
+package iptables
+
+import "os/exec"
+
+type CmdRunner interface {
+	Run(cmd *exec.Cmd) (output string, err error)
+}
+
+type Logger interface {
+	Debug(s string)
+	Info(s string)
+	Warn(s string)
+	Error(s string)
+}

internal/firewall/iptables/ip6tables.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -14,8 +14,8 @@ import (
 func findIP6tablesSupported(ctx context.Context, runner CmdRunner) (
 	ip6tablesPath string, err error,
 ) {
-	ip6tablesPath, err = checkIptablesSupport(ctx, runner, "ip6tables", "ip6tables-nft", "ip6tables-legacy")
-	if errors.Is(err, ErrIPTablesNotSupported) {
+	ip6tablesPath, err = checkIptablesSupport(ctx, runner, "ip6tables", "ip6tables-legacy")
+	if errors.Is(err, ErrNotSupported) {
 		return "", nil
 	} else if err != nil {
 		return "", err
@@ -56,7 +56,7 @@ func (c *Config) runIP6tablesInstruction(ctx context.Context, instruction string
 
 var ErrPolicyNotValid = errors.New("policy is not valid")
 
-func (c *Config) setIPv6AllPolicies(ctx context.Context, policy string) error {
+func (c *Config) SetIPv6AllPolicies(ctx context.Context, policy string) error {
 	switch policy {
 	case "ACCEPT", "DROP":
 	default:

internal/firewall/iptables/iptables.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -53,7 +53,7 @@ func (c *Config) Version(ctx context.Context) (string, error) {
 	if len(words) < minWords {
 		return "", fmt.Errorf("%w: %s", ErrIPTablesVersionTooShort, output)
 	}
-	return words[1], nil
+	return "iptables " + words[1], nil
 }
 
 func (c *Config) runIptablesInstructions(ctx context.Context, instructions []string) error {
@@ -84,7 +84,7 @@ func (c *Config) runIptablesInstruction(ctx context.Context, instruction string)
 	return nil
 }
 
-func (c *Config) clearAllRules(ctx context.Context) error {
+func (c *Config) ClearAllRules(ctx context.Context) error {
 	tables := []string{"filter"}
 	for _, table := range tables {
 		return c.runMixedIptablesInstructions(ctx, []string{
@@ -95,7 +95,7 @@ func (c *Config) clearAllRules(ctx context.Context) error {
 	return nil
 }
 
-func (c *Config) setIPv4AllPolicies(ctx context.Context, policy string) error {
+func (c *Config) SetIPv4AllPolicies(ctx context.Context, policy string) error {
 	switch policy {
 	case "ACCEPT", "DROP":
 	default:
@@ -108,13 +108,13 @@ func (c *Config) setIPv4AllPolicies(ctx context.Context, policy string) error {
 	})
 }
 
-func (c *Config) acceptInputThroughInterface(ctx context.Context, intf string, remove bool) error {
+func (c *Config) AcceptInputThroughInterface(ctx context.Context, intf string, remove bool) error {
 	return c.runMixedIptablesInstruction(ctx, fmt.Sprintf(
 		"%s INPUT -i %s -j ACCEPT", appendOrDelete(remove), intf,
 	))
 }
 
-func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
+func (c *Config) AcceptInputToSubnet(ctx context.Context, intf string,
 	destination netip.Prefix, remove bool,
 ) error {
 	interfaceFlag := "-i " + intf
@@ -134,20 +134,20 @@ func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-func (c *Config) acceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error {
+func (c *Config) AcceptOutputThroughInterface(ctx context.Context, intf string, remove bool) error {
 	return c.runMixedIptablesInstruction(ctx, fmt.Sprintf(
 		"%s OUTPUT -o %s -j ACCEPT", appendOrDelete(remove), intf,
 	))
 }
 
-func (c *Config) acceptEstablishedRelatedTraffic(ctx context.Context, remove bool) error {
+func (c *Config) AcceptEstablishedRelatedTraffic(ctx context.Context, remove bool) error {
 	return c.runMixedIptablesInstructions(ctx, []string{
 		fmt.Sprintf("%s OUTPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT", appendOrDelete(remove)),
 		fmt.Sprintf("%s INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT", appendOrDelete(remove)),
 	})
 }
 
-func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
+func (c *Config) AcceptOutputTrafficToVPN(ctx context.Context,
 	defaultInterface string, connection models.Connection, remove bool,
 ) error {
 	protocol := connection.Protocol
@@ -165,8 +165,11 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
+// AcceptOutputFromIPToSubnet accepts outgoing traffic from sourceIP to destinationSubnet
+// on the interface intf. If intf is empty, it is set to "*" which means all interfaces.
+// If remove is true, the rule is removed instead of added.
 // Thanks to @npawelek.
-func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
+func (c *Config) AcceptOutputFromIPToSubnet(ctx context.Context,
 	intf string, sourceIP netip.Addr, destinationSubnet netip.Prefix, remove bool,
 ) error {
 	doIPv4 := sourceIP.Is4() && destinationSubnet.Addr().Is4()
@@ -187,8 +190,11 @@ func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-// NDP uses multicast address (theres no broadcast in IPv6 like ARP uses in IPv4).
-func (c *Config) acceptIpv6MulticastOutput(ctx context.Context,
+// AcceptIpv6MulticastOutput accepts outgoing traffic to the IPv6 multicast address
+// ff02::1:ff00:0/104, which is used for NDP (Neighbor Discovery Protocol) to resolve
+// IPv6 addresses to MAC addresses. If intf is empty, it is set to "*" which means
+// all interfaces. If remove is true, the rule is removed instead of added.
+func (c *Config) AcceptIpv6MulticastOutput(ctx context.Context,
 	intf string, remove bool,
 ) error {
 	interfaceFlag := "-o " + intf
@@ -200,8 +206,11 @@ func (c *Config) acceptIpv6MulticastOutput(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-// Used for port forwarding, with intf set to tun.
-func (c *Config) acceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error {
+// AcceptInputToPort accepts incoming traffic on the specified port, for both TCP and UDP
+// protocols, on the interface intf. If intf is empty, it is set to "*" which means all interfaces.
+// If remove is true, the rule is removed instead of added. This is used for port forwarding, with
+// intf set to the VPN tunnel interface.
+func (c *Config) AcceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error {
 	interfaceFlag := "-i " + intf
 	if intf == "*" { // all interfaces
 		interfaceFlag = ""
@@ -212,8 +221,12 @@ func (c *Config) acceptInputToPort(ctx context.Context, intf string, port uint16
 	})
 }
 
-// Used for VPN server side port forwarding, with intf set to the VPN tunnel interface.
-func (c *Config) redirectPort(ctx context.Context, intf string,
+// RedirectPort redirects incoming traffic on the specified source port to the
+// specified destination port, for both TCP and UDP protocols, on the interface intf.
+// If intf is empty, it is set to "*" which means all interfaces. If remove is true,
+// the redirection is removed instead of added. This is used for VPN server side
+// port forwarding, with intf set to the VPN tunnel interface.
+func (c *Config) RedirectPort(ctx context.Context, intf string,
 	sourcePort, destinationPort uint16, remove bool,
 ) (err error) {
 	interfaceFlag := "-i " + intf
@@ -260,7 +273,7 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 	return nil
 }
 
-func (c *Config) runUserPostRules(ctx context.Context, filepath string, remove bool) error {
+func (c *Config) RunUserPostRules(ctx context.Context, filepath string, remove bool) error {
 	file, err := os.OpenFile(filepath, os.O_RDONLY, 0)
 	if os.IsNotExist(err) {
 		return nil

internal/firewall/iptables/iptablesmix.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"

internal/firewall/iptables/list.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"errors"

internal/firewall/iptables/list_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"net/netip"

internal/firewall/iptables/mocks_generate_test.go

@@ -1,3 +1,3 @@
-package firewall
+package iptables
 
 //go:generate mockgen -destination=mocks_test.go -package $GOPACKAGE . CmdRunner,Logger

internal/firewall/iptables/mocks_test.go

@@ -1,8 +1,8 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/qdm12/gluetun/internal/firewall (interfaces: CmdRunner,Logger)
+// Source: github.com/qdm12/gluetun/internal/firewall/iptables (interfaces: CmdRunner,Logger)
 
-// Package firewall is a generated GoMock package.
-package firewall
+// Package iptables is a generated GoMock package.
+package iptables
 
 import (
 	exec "os/exec"

internal/firewall/iptables/parse.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"errors"

internal/firewall/iptables/parse_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"net/netip"

internal/firewall/iptables/support.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -11,10 +11,10 @@ import (
 )
 
 var (
-	ErrNetAdminMissing      = errors.New("NET_ADMIN capability is missing")
-	ErrTestRuleCleanup      = errors.New("failed cleaning up test rule")
-	ErrInputPolicyNotFound  = errors.New("input policy not found")
-	ErrIPTablesNotSupported = errors.New("no iptables supported found")
+	ErrNetAdminMissing     = errors.New("NET_ADMIN capability is missing")
+	ErrTestRuleCleanup     = errors.New("failed cleaning up test rule")
+	ErrInputPolicyNotFound = errors.New("input policy not found")
+	ErrNotSupported        = errors.New("no iptables supported found")
 )
 
 func checkIptablesSupport(ctx context.Context, runner CmdRunner,
@@ -57,7 +57,7 @@ func checkIptablesSupport(ctx context.Context, runner CmdRunner,
 	}
 
 	return "", fmt.Errorf("%w: errors encountered are: %s",
-		ErrIPTablesNotSupported, strings.Join(allUnsupportedMessages, "; "))
+		ErrNotSupported, strings.Join(allUnsupportedMessages, "; "))
 }
 
 func testIptablesPath(ctx context.Context, path string,

internal/firewall/iptables/support_test.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"
@@ -101,7 +101,7 @@ func Test_checkIptablesSupport(t *testing.T) {
 				return runner
 			},
 			iptablesPathsToTry: []string{"path1", "path2"},
-			errSentinel:        ErrIPTablesNotSupported,
+			errSentinel:        ErrNotSupported,
 			errMessage: "no iptables supported found: " +
 				"errors encountered are: " +
 				"path1: output 1 (exit code 4); " +

internal/firewall/iptables/tcp.go

@@ -1,4 +1,4 @@
-package firewall
+package iptables
 
 import (
 	"context"

internal/firewall/outboundsubnets.go

@@ -48,7 +48,7 @@ func (c *Config) removeOutboundSubnets(ctx context.Context, subnets []netip.Pref
 			}
 
 			firewallUpdated = true
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subNet, remove)
 			if err != nil {
 				c.logger.Error("cannot remove outdated outbound subnet: " + err.Error())
@@ -77,7 +77,7 @@ func (c *Config) addOutboundSubnets(ctx context.Context, subnets []netip.Prefix)
 			}
 
 			firewallUpdated = true
-			err := c.acceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
+			err := c.impl.AcceptOutputFromIPToSubnet(ctx, defaultRoute.NetInterface,
 				defaultRoute.AssignedIP, subnet, remove)
 			if err != nil {
 				return err

internal/firewall/ports.go

@@ -35,7 +35,7 @@ func (c *Config) SetAllowedPort(ctx context.Context, port uint16, intf string) (
 	c.logger.Info("setting allowed input port " + fmt.Sprint(port) + " through interface " + intf + "...")
 
 	const remove = false
-	if err := c.acceptInputToPort(ctx, intf, port, remove); err != nil {
+	if err := c.impl.AcceptInputToPort(ctx, intf, port, remove); err != nil {
 		return fmt.Errorf("allowing input to port %d through interface %s: %w",
 			port, intf, err)
 	}
@@ -68,7 +68,7 @@ func (c *Config) RemoveAllowedPort(ctx context.Context, port uint16) (err error)
 
 	const remove = true
 	for netInterface := range interfacesSet {
-		err := c.acceptInputToPort(ctx, netInterface, port, remove)
+		err := c.impl.AcceptInputToPort(ctx, netInterface, port, remove)
 		if err != nil {
 			return fmt.Errorf("removing allowed port %d on interface %s: %w",
 				port, netInterface, err)

internal/firewall/redirect.go

@@ -50,7 +50,7 @@ func (c *Config) RedirectPort(ctx context.Context, intf string, sourcePort,
 		return nil
 	case conflict != nil:
 		const remove = true
-		err = c.redirectPort(ctx, conflict.interfaceName, conflict.sourcePort,
+		err = c.impl.RedirectPort(ctx, conflict.interfaceName, conflict.sourcePort,
 			conflict.destinationPort, remove)
 		if err != nil {
 			return fmt.Errorf("removing conflicting redirection: %w", err)
@@ -60,7 +60,7 @@ func (c *Config) RedirectPort(ctx context.Context, intf string, sourcePort,
 	}
 
 	const remove = false
-	err = c.redirectPort(ctx, intf, sourcePort, destinationPort, remove)
+	err = c.impl.RedirectPort(ctx, intf, sourcePort, destinationPort, remove)
 	if err != nil {
 		return fmt.Errorf("redirecting port: %w", err)
 	}

internal/firewall/vpn.go

@@ -28,7 +28,7 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	remove := true
 	if c.vpnConnection.IP.IsValid() {
 		for _, defaultRoute := range c.defaultRoutes {
-			if err := c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove); err != nil {
+			if err := c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove); err != nil {
 				c.logger.Error("cannot remove outdated VPN connection rule: " + err.Error())
 			}
 		}
@@ -36,7 +36,7 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	c.vpnConnection = models.Connection{}
 
 	if c.vpnIntf != "" {
-		if err = c.acceptOutputThroughInterface(ctx, c.vpnIntf, remove); err != nil {
+		if err = c.impl.AcceptOutputThroughInterface(ctx, c.vpnIntf, remove); err != nil {
 			c.logger.Error("cannot remove outdated VPN interface rule: " + err.Error())
 		}
 	}
@@ -45,13 +45,13 @@ func (c *Config) SetVPNConnection(ctx context.Context,
 	remove = false
 
 	for _, defaultRoute := range c.defaultRoutes {
-		if err := c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, connection, remove); err != nil {
+		if err := c.impl.AcceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, connection, remove); err != nil {
 			return fmt.Errorf("allowing output traffic through VPN connection: %w", err)
 		}
 	}
 	c.vpnConnection = connection
 
-	if err = c.acceptOutputThroughInterface(ctx, vpnIntf, remove); err != nil {
+	if err = c.impl.AcceptOutputThroughInterface(ctx, vpnIntf, remove); err != nil {
 		return fmt.Errorf("accepting output traffic through interface %s: %w", vpnIntf, err)
 	}
 	c.vpnIntf = vpnIntf

internal/firewall/wrappers.go

@@ -0,0 +1,21 @@
+package firewall
+
+import (
+	"context"
+	"net/netip"
+)
+
+func (c *Config) Version(ctx context.Context) (version string, err error) {
+	return c.impl.Version(ctx)
+}
+
+// TempDropOutputTCPRST temporarily drops outgoing TCP RST packets to the specified address and port,
+// for any TCP packets not marked with the excludeMark given.
+// This is necessary for TCP path MTU discovery to work, as the kernel will try to terminate the connection
+// by sending a TCP RST packet, although we want to handle the connection manually.
+func (c *Config) TempDropOutputTCPRST(ctx context.Context,
+	src, dst netip.AddrPort, excludeMark int) (
+	revert func(ctx context.Context) error, err error,
+) {
+	return c.impl.TempDropOutputTCPRST(ctx, src, dst, excludeMark)
+}

internal/pmtud/pmtud.go

@@ -7,7 +7,7 @@ import (
 	"net/netip"
 	"time"
 
-	"github.com/qdm12/gluetun/internal/firewall"
+	"github.com/qdm12/gluetun/internal/firewall/iptables"
 	"github.com/qdm12/gluetun/internal/pmtud/constants"
 	"github.com/qdm12/gluetun/internal/pmtud/icmp"
 	"github.com/qdm12/gluetun/internal/pmtud/tcp"
@@ -71,7 +71,7 @@ func PathMTUDiscover(ctx context.Context, icmpAddrs []netip.Addr, tcpAddrs []net
 	}
 	mtu, err = tcp.PathMTUDiscover(ctx, tcpAddrs, minMTU, maxPossibleMTU, tryTimeout, fw, logger)
 	if err != nil {
-		if errors.Is(err, firewall.ErrMarkMatchModuleMissing) {
+		if errors.Is(err, iptables.ErrMarkMatchModuleMissing) {
 			logger.Debugf("aborting TCP path MTU discovery: %s", err)
 			if icmpSuccess {
 				return maxPossibleMTU, nil // only rely on ICMP PMTUD results

internal/pmtud/tcp/helpers_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/qdm12/gluetun/internal/command"
 	"github.com/qdm12/gluetun/internal/firewall"
+	"github.com/qdm12/gluetun/internal/firewall/iptables"
 	"github.com/qdm12/gluetun/internal/netlink"
 	"github.com/qdm12/gluetun/internal/pmtud/constants"
 	"github.com/qdm12/gluetun/internal/routing"
@@ -35,7 +36,7 @@ func getFirewall(t *testing.T) *firewall.Config {
 		cmder := command.New()
 		var err error
 		testFirewall, err = firewall.NewConfig(t.Context(), noopLogger, cmder, nil, nil)
-		if errors.Is(err, firewall.ErrIPTablesNotSupported) {
+		if errors.Is(err, iptables.ErrNotSupported) {
 			t.Skip("iptables not installed, skipping TCP PMTUD tests")
 		}
 		require.NoError(t, err, "creating firewall config")

internal/pmtud/tcp/mss.go

@@ -7,7 +7,7 @@ import (
 	"net/netip"
 	"time"
 
-	"github.com/qdm12/gluetun/internal/firewall"
+	"github.com/qdm12/gluetun/internal/firewall/iptables"
 	"github.com/qdm12/gluetun/internal/pmtud/constants"
 	"github.com/qdm12/gluetun/internal/pmtud/ip"
 )
@@ -43,7 +43,7 @@ func findHighestMSSDestination(ctx context.Context, familyToFD map[int]fileDescr
 		if result.err != nil {
 			switch {
 			case err != nil: // error already occurred for another findMSS goroutine
-			case errors.Is(result.err, firewall.ErrMarkMatchModuleMissing):
+			case errors.Is(result.err, iptables.ErrMarkMatchModuleMissing):
 				err = fmt.Errorf("finding MSS for %s: %w", result.dst, result.err)
 			case dst.Addr().Is6() && errors.Is(result.err, ip.ErrNetworkUnreachable):
 				// silently discard IPv6 network unreachable errors since they are common