feat(server): role based authentication system (#2434)

- Parse toml configuration file, see https://github.com/qdm12/gluetun-wiki/blob/main/setup/advanced/control-server.md#authentication
- Retro-compatible with existing AND documented routes, until after v3.41 release
- Log a warning if an unprotected-by-default route is accessed unprotected
- Authentication methods: none, apikey, basic
- `genkey` command to generate API keys
- move log middleware to internal/server/middlewares/log

Co-authored-by: Joe Jose <45399349+joejose97@users.noreply.github.com>

Dockerfile

@@ -197,6 +197,7 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Control server
     HTTP_CONTROL_SERVER_LOG=on \
     HTTP_CONTROL_SERVER_ADDRESS=":8000" \
+    HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH=/gluetun/auth/config.toml \
     # Server data updater
     UPDATER_PERIOD=0 \
     UPDATER_MIN_RATIO=0.8 \

cmd/gluetun/main.go

@@ -161,12 +161,14 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 			return cli.Update(ctx, args[2:], logger)
 		case "format-servers":
 			return cli.FormatServers(args[2:])
+		case "genkey":
+			return cli.GenKey(args[2:])
 		default:
 			return fmt.Errorf("%w: %s", errCommandUnknown, args[1])
 		}
 	}
 
-	announcementExp, err := time.Parse(time.RFC3339, "2023-07-01T00:00:00Z")
+	announcementExp, err := time.Parse(time.RFC3339, "2024-12-01T00:00:00Z")
 	if err != nil {
 		return err
 	}
@@ -177,7 +179,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		Version:      buildInfo.Version,
 		Commit:       buildInfo.Commit,
 		Created:      buildInfo.Created,
-		Announcement: "Wiki moved to https://github.com/qdm12/gluetun-wiki",
+		Announcement: "All control server routes will become private by default after the v3.41.0 release",
 		AnnounceExp:  announcementExp,
 		// Sponsor information
 		PaypalUser:    "qmcgaw",
@@ -474,6 +476,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		"http server", goroutine.OptionTimeout(defaultShutdownTimeout))
 	httpServer, err := server.New(httpServerCtx, controlServerAddress, controlServerLogging,
 		logger.New(log.SetComponent("http server")),
+		allSettings.ControlServer.AuthFilePath,
 		buildInfo, vpnLooper, portForwardLooper, unboundLooper, updaterLooper, publicIPLooper,
 		storage, ipv6Supported)
 	if err != nil {
@@ -595,6 +598,7 @@ type clier interface {
 	OpenvpnConfig(logger cli.OpenvpnConfigLogger, reader *reader.Reader, ipv6Checker cli.IPv6Checker) error
 	HealthCheck(ctx context.Context, reader *reader.Reader, warner cli.Warner) error
 	Update(ctx context.Context, args []string, logger cli.UpdaterLogger) error
+	GenKey(args []string) error
 }
 
 type Tun interface {

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/golang/mock v1.6.0
 	github.com/klauspost/compress v1.17.8
 	github.com/klauspost/pgzip v1.2.6
+	github.com/pelletier/go-toml/v2 v2.2.2
 	github.com/qdm12/dns v1.11.0
 	github.com/qdm12/golibs v0.0.0-20210822203818-5c568b0777b6
 	github.com/qdm12/gosettings v0.4.2

go.sum

@@ -83,6 +83,8 @@ github.com/mr-tron/base58 v1.2.0 h1:T/HDJBh4ZCPbU39/+c3rRvE0uKBQlU27+QI8LJ4t64o=
 github.com/mr-tron/base58 v1.2.0/go.mod h1:BinMc/sQntlIE1frQmRFPUoPA1Zkr8VRgBdjWI2mNwc=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pelletier/go-buffruneio v0.2.0/go.mod h1:JkE26KsDizTr40EUHkXVtNPvgGtbSNq5BcowyYOWdKo=
+github.com/pelletier/go-toml/v2 v2.2.2 h1:aYUidT7k73Pcl9nb2gScu7NSrKCSHIDE89b3+6Wq+LM=
+github.com/pelletier/go-toml/v2 v2.2.2/go.mod h1:1t835xjRzz80PqgE6HHgN2JOsmgYu/h4qDAS4n929Rs=
 github.com/phayes/permbits v0.0.0-20190612203442-39d7c581d2ee/go.mod h1:3uODdxMgOaPYeWU7RzZLxVtJHZ/x1f/iHkBZuKJDzuY=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -113,10 +115,16 @@ github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAm
 github.com/src-d/gcfg v1.4.0/go.mod h1:p/UMsR43ujA89BJY9duynAwIpvqEujIH/jFlfL7jWoI=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/ulikunitz/xz v0.5.11 h1:kpFauv27b6ynzBNT/Xy+1k+fK4WswhN/6PN5WhFAGw8=

internal/cli/genkey.go

@@ -0,0 +1,66 @@
+package cli
+
+import (
+	"crypto/rand"
+	"flag"
+	"fmt"
+)
+
+func (c *CLI) GenKey(args []string) (err error) {
+	flagSet := flag.NewFlagSet("genkey", flag.ExitOnError)
+	err = flagSet.Parse(args)
+	if err != nil {
+		return fmt.Errorf("parsing flags: %w", err)
+	}
+
+	const keyLength = 128 / 8
+	keyBytes := make([]byte, keyLength)
+
+	_, _ = rand.Read(keyBytes)
+
+	key := base58Encode(keyBytes)
+	fmt.Println(key)
+
+	return nil
+}
+
+func base58Encode(data []byte) string {
+	const alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
+	const radix = 58
+
+	zcount := 0
+	for zcount < len(data) && data[zcount] == 0 {
+		zcount++
+	}
+
+	// integer simplification of ceil(log(256)/log(58))
+	ceilLog256Div58 := (len(data)-zcount)*555/406 + 1 //nolint:gomnd
+	size := zcount + ceilLog256Div58
+
+	output := make([]byte, size)
+
+	high := size - 1
+	for _, b := range data {
+		i := size - 1
+		for carry := uint32(b); i > high || carry != 0; i-- {
+			carry += 256 * uint32(output[i]) //nolint:gomnd
+			output[i] = byte(carry % radix)
+			carry /= radix
+		}
+		high = i
+	}
+
+	// Determine the additional "zero-gap" in the output buffer
+	additionalZeroGapEnd := zcount
+	for additionalZeroGapEnd < size && output[additionalZeroGapEnd] == 0 {
+		additionalZeroGapEnd++
+	}
+
+	val := output[additionalZeroGapEnd-zcount:]
+	size = len(val)
+	for i := range val {
+		output[i] = alphabet[val[i]]
+	}
+
+	return string(output[:size])
+}

internal/configuration/settings/server.go

@@ -19,6 +19,11 @@ type ControlServer struct {
 	// Log can be true or false to enable logging on requests.
 	// It cannot be nil in the internal state.
 	Log *bool
+	// AuthFilePath is the path to the file containing the authentication
+	// configuration for the middleware.
+	// It cannot be empty in the internal state and defaults to
+	// /gluetun/auth/config.toml.
+	AuthFilePath string
 }
 
 func (c ControlServer) validate() (err error) {
@@ -44,8 +49,9 @@ func (c ControlServer) validate() (err error) {
 
 func (c *ControlServer) copy() (copied ControlServer) {
 	return ControlServer{
-		Address: gosettings.CopyPointer(c.Address),
+		Address:      gosettings.CopyPointer(c.Address),
-		Log:     gosettings.CopyPointer(c.Log),
+		Log:          gosettings.CopyPointer(c.Log),
+		AuthFilePath: c.AuthFilePath,
 	}
 }
 
@@ -55,11 +61,13 @@ func (c *ControlServer) copy() (copied ControlServer) {
 func (c *ControlServer) overrideWith(other ControlServer) {
 	c.Address = gosettings.OverrideWithPointer(c.Address, other.Address)
 	c.Log = gosettings.OverrideWithPointer(c.Log, other.Log)
+	c.AuthFilePath = gosettings.OverrideWithComparable(c.AuthFilePath, other.AuthFilePath)
 }
 
 func (c *ControlServer) setDefaults() {
 	c.Address = gosettings.DefaultPointer(c.Address, ":8000")
 	c.Log = gosettings.DefaultPointer(c.Log, true)
+	c.AuthFilePath = gosettings.DefaultComparable(c.AuthFilePath, "/gluetun/auth/config.toml")
 }
 
 func (c ControlServer) String() string {
@@ -70,6 +78,7 @@ func (c ControlServer) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Control server settings:")
 	node.Appendf("Listening address: %s", *c.Address)
 	node.Appendf("Logging: %s", gosettings.BoolToYesNo(c.Log))
+	node.Appendf("Authentication file path: %s", c.AuthFilePath)
 	return node
 }
 
@@ -78,6 +87,10 @@ func (c *ControlServer) read(r *reader.Reader) (err error) {
 	if err != nil {
 		return err
 	}
+
 	c.Address = r.Get("HTTP_CONTROL_SERVER_ADDRESS")
+
+	c.AuthFilePath = r.String("HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH")
+
 	return nil
 }

internal/configuration/settings/serverselection.go

@@ -191,11 +191,19 @@ func validateServerFilters(settings ServerSelection, filterChoices models.Filter
 		return fmt.Errorf("%w: %w", ErrHostnameNotValid, err)
 	}
 
-	if vpnServiceProvider == providers.Custom && len(settings.Names) == 1 {
+	if vpnServiceProvider == providers.Custom {
-		// Allow a single name to be specified for the custom provider in case
+		switch len(settings.Names) {
-		// the user wants to use VPN server side port forwarding with PIA
+		case 0:
-		// which requires a server name for TLS verification.
+		case 1:
-		filterChoices.Names = settings.Names
+			// Allow a single name to be specified for the custom provider in case
+			// the user wants to use VPN server side port forwarding with PIA
+			// which requires a server name for TLS verification.
+			filterChoices.Names = settings.Names
+		default:
+			return fmt.Errorf("%w: %d names specified instead of "+
+				"0 or 1 for the custom provider",
+				ErrNameNotValid, len(settings.Names))
+		}
 	}
 	err = validate.AreAllOneOfCaseInsensitive(settings.Names, filterChoices.Names)
 	if err != nil {
@@ -229,6 +237,8 @@ func validateFeatureFilters(settings ServerSelection, vpnServiceProvider string)
 	switch {
 	case *settings.OwnedOnly && vpnServiceProvider != providers.Mullvad:
 		return fmt.Errorf("%w", ErrOwnedOnlyNotSupported)
+	case vpnServiceProvider == providers.Protonvpn && *settings.FreeOnly && *settings.PortForwardOnly:
+		return fmt.Errorf("%w: together with free only filter", ErrPortForwardOnlyNotSupported)
 	case *settings.StreamOnly &&
 		!helpers.IsOneOf(vpnServiceProvider, providers.Protonvpn, providers.VPNUnlimited):
 		return fmt.Errorf("%w", ErrStreamOnlyNotSupported)

internal/configuration/settings/settings_test.go

@@ -78,7 +78,8 @@ func Test_Settings_String(t *testing.T) {
 |   └── Enabled: no
 ├── Control server settings:
 |   ├── Listening address: :8000
-|   └── Logging: yes
+|   ├── Logging: yes
+|   └── Authentication file path: /gluetun/auth/config.toml
 ├── OS Alpine settings:
 |   ├── Process UID: 1000
 |   └── Process GID: 1000

internal/firewall/delete.go

@@ -0,0 +1,98 @@
+package firewall
+
+import (
+	"context"
+	"fmt"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+// isDeleteMatchInstruction returns true if the iptables instruction
+// is a delete instruction by rule matching. It returns false if the
+// instruction is a delete instruction by line number, or not a delete
+// instruction.
+func isDeleteMatchInstruction(instruction string) bool {
+	fields := strings.Fields(instruction)
+	for i, field := range fields {
+		switch {
+		case field != "-D" && field != "--delete": //nolint:goconst
+			continue
+		case i == len(fields)-1: // malformed: missing chain name
+			return false
+		case i == len(fields)-2: // chain name is last field
+			return true
+		default:
+			// chain name is fields[i+1]
+			const base, bitLength = 10, 16
+			_, err := strconv.ParseUint(fields[i+2], base, bitLength)
+			return err != nil // not a line number
+		}
+	}
+	return false
+}
+
+func deleteIPTablesRule(ctx context.Context, iptablesBinary, instruction string,
+	runner Runner, logger Logger) (err error) {
+	targetRule, err := parseIptablesInstruction(instruction)
+	if err != nil {
+		return fmt.Errorf("parsing iptables command: %w", err)
+	}
+
+	lineNumber, err := findLineNumber(ctx, iptablesBinary,
+		targetRule, runner, logger)
+	if err != nil {
+		return fmt.Errorf("finding iptables chain rule line number: %w", err)
+	} else if lineNumber == 0 {
+		logger.Debug("rule matching \"" + instruction + "\" not found")
+		return nil
+	}
+	logger.Debug(fmt.Sprintf("found iptables chain rule matching %q at line number %d",
+		instruction, lineNumber))
+
+	cmd := exec.CommandContext(ctx, iptablesBinary, "-t", targetRule.table,
+		"-D", targetRule.chain, fmt.Sprint(lineNumber)) // #nosec G204
+	logger.Debug(cmd.String())
+	output, err := runner.Run(cmd)
+	if err != nil {
+		err = fmt.Errorf("command failed: %q: %w", cmd, err)
+		if output != "" {
+			err = fmt.Errorf("%w: %s", err, output)
+		}
+		return err
+	}
+
+	return nil
+}
+
+// findLineNumber finds the line number of an iptables rule.
+// It returns 0 if the rule is not found.
+func findLineNumber(ctx context.Context, iptablesBinary string,
+	instruction iptablesInstruction, runner Runner, logger Logger) (
+	lineNumber uint16, err error) {
+	listFlags := []string{"-t", instruction.table, "-L", instruction.chain,
+		"--line-numbers", "-n", "-v"}
+	cmd := exec.CommandContext(ctx, iptablesBinary, listFlags...) // #nosec G204
+	logger.Debug(cmd.String())
+	output, err := runner.Run(cmd)
+	if err != nil {
+		err = fmt.Errorf("command failed: %q: %w", cmd, err)
+		if output != "" {
+			err = fmt.Errorf("%w: %s", err, output)
+		}
+		return 0, err
+	}
+
+	chain, err := parseChain(output)
+	if err != nil {
+		return 0, fmt.Errorf("parsing chain list: %w", err)
+	}
+
+	for _, rule := range chain.rules {
+		if instruction.equalToRule(instruction.table, chain.name, rule) {
+			return rule.lineNumber, nil
+		}
+	}
+
+	return 0, nil
+}

internal/firewall/delete_test.go

@@ -0,0 +1,188 @@
+package firewall
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_isDeleteMatchInstruction(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		instruction   string
+		isDeleteMatch bool
+	}{
+		"not_delete": {
+			instruction: "-t nat -A PREROUTING -i tun0 -j ACCEPT",
+		},
+		"malformed_missing_chain_name": {
+			instruction: "-t nat -D",
+		},
+		"delete_chain_name_last_field": {
+			instruction:   "-t nat --delete PREROUTING",
+			isDeleteMatch: true,
+		},
+		"delete_match": {
+			instruction:   "-t nat --delete PREROUTING -i tun0 -j ACCEPT",
+			isDeleteMatch: true,
+		},
+		"delete_line_number_last_field": {
+			instruction: "-t nat -D PREROUTING 2",
+		},
+		"delete_line_number": {
+			instruction: "-t nat -D PREROUTING 2 -i tun0 -j ACCEPT",
+		},
+	}
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			isDeleteMatch := isDeleteMatchInstruction(testCase.instruction)
+
+			assert.Equal(t, testCase.isDeleteMatch, isDeleteMatch)
+		})
+	}
+}
+
+func newCmdMatcherListRules(iptablesBinary, table, chain string) *cmdMatcher { //nolint:unparam
+	return newCmdMatcher(iptablesBinary, "^-t$", "^"+table+"$", "^-L$", "^"+chain+"$",
+		"^--line-numbers$", "^-n$", "^-v$")
+}
+
+func Test_deleteIPTablesRule(t *testing.T) {
+	t.Parallel()
+
+	const iptablesBinary = "/sbin/iptables"
+	errTest := errors.New("test error")
+
+	testCases := map[string]struct {
+		instruction string
+		makeRunner  func(ctrl *gomock.Controller) *MockRunner
+		makeLogger  func(ctrl *gomock.Controller) *MockLogger
+		errWrapped  error
+		errMessage  string
+	}{
+		"invalid_instruction": {
+			instruction: "invalid",
+			errWrapped:  ErrIptablesCommandMalformed,
+			errMessage: "parsing iptables command: iptables command is malformed: " +
+				"fields count 1 is not even: \"invalid\"",
+		},
+		"list_error": {
+			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",
+			makeRunner: func(ctrl *gomock.Controller) *MockRunner {
+				runner := NewMockRunner(ctrl)
+				runner.EXPECT().
+					Run(newCmdMatcherListRules(iptablesBinary, "nat", "PREROUTING")).
+					Return("", errTest)
+				return runner
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockLogger {
+				logger := NewMockLogger(ctrl)
+				logger.EXPECT().Debug("/sbin/iptables -t nat -L PREROUTING --line-numbers -n -v")
+				return logger
+			},
+			errWrapped: errTest,
+			errMessage: `finding iptables chain rule line number: command failed: ` +
+				`"/sbin/iptables -t nat -L PREROUTING --line-numbers -n -v": test error`,
+		},
+		"rule_not_found": {
+			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",
+			makeRunner: func(ctrl *gomock.Controller) *MockRunner {
+				runner := NewMockRunner(ctrl)
+				runner.EXPECT().Run(newCmdMatcherListRules(iptablesBinary, "nat", "PREROUTING")).
+					Return(`Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
+		num   pkts bytes target     prot opt in     out     source               destination
+		1        0     0 REDIRECT   6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:5000 redir ports 9999`, //nolint:lll
+						nil)
+				return runner
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockLogger {
+				logger := NewMockLogger(ctrl)
+				logger.EXPECT().Debug("/sbin/iptables -t nat -L PREROUTING --line-numbers -n -v")
+				logger.EXPECT().Debug("rule matching \"-t nat --delete PREROUTING " +
+					"-i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678\" not found")
+				return logger
+			},
+		},
+		"rule_found_delete_error": {
+			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",
+			makeRunner: func(ctrl *gomock.Controller) *MockRunner {
+				runner := NewMockRunner(ctrl)
+				runner.EXPECT().Run(newCmdMatcherListRules(iptablesBinary, "nat", "PREROUTING")).
+					Return("Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)\n"+
+						"num   pkts bytes target     prot opt in     out     source               destination         \n"+
+						"1        0     0 REDIRECT   6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:5000 redir ports 9999\n"+ //nolint:lll
+						"2        0     0 REDIRECT   6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:43716 redir ports 5678\n", //nolint:lll
+						nil)
+				runner.EXPECT().Run(newCmdMatcher(iptablesBinary, "^-t$", "^nat$",
+					"^-D$", "^PREROUTING$", "^2$")).Return("details", errTest)
+				return runner
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockLogger {
+				logger := NewMockLogger(ctrl)
+				logger.EXPECT().Debug("/sbin/iptables -t nat -L PREROUTING --line-numbers -n -v")
+				logger.EXPECT().Debug("found iptables chain rule matching \"-t nat --delete PREROUTING " +
+					"-i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678\" at line number 2")
+				logger.EXPECT().Debug("/sbin/iptables -t nat -D PREROUTING 2")
+				return logger
+			},
+			errWrapped: errTest,
+			errMessage: "command failed: \"/sbin/iptables -t nat -D PREROUTING 2\": test error: details",
+		},
+		"rule_found_delete_success": {
+			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",
+			makeRunner: func(ctrl *gomock.Controller) *MockRunner {
+				runner := NewMockRunner(ctrl)
+				runner.EXPECT().Run(newCmdMatcherListRules(iptablesBinary, "nat", "PREROUTING")).
+					Return("Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)\n"+
+						"num   pkts bytes target     prot opt in     out     source               destination         \n"+
+						"1        0     0 REDIRECT   6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:5000 redir ports 9999\n"+ //nolint:lll
+						"2        0     0 REDIRECT   6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:43716 redir ports 5678\n", //nolint:lll
+						nil)
+				runner.EXPECT().Run(newCmdMatcher(iptablesBinary, "^-t$", "^nat$",
+					"^-D$", "^PREROUTING$", "^2$")).Return("", nil)
+				return runner
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockLogger {
+				logger := NewMockLogger(ctrl)
+				logger.EXPECT().Debug("/sbin/iptables -t nat -L PREROUTING --line-numbers -n -v")
+				logger.EXPECT().Debug("found iptables chain rule matching \"-t nat --delete PREROUTING " +
+					"-i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678\" at line number 2")
+				logger.EXPECT().Debug("/sbin/iptables -t nat -D PREROUTING 2")
+				return logger
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			ctrl := gomock.NewController(t)
+
+			ctx := context.Background()
+			instruction := testCase.instruction
+			var runner *MockRunner
+			if testCase.makeRunner != nil {
+				runner = testCase.makeRunner(ctrl)
+			}
+			var logger *MockLogger
+			if testCase.makeLogger != nil {
+				logger = testCase.makeLogger(ctrl)
+			}
+
+			err := deleteIPTablesRule(ctx, iptablesBinary, instruction, runner, logger)
+
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+		})
+	}
+}

internal/firewall/interfaces.go

@@ -0,0 +1,13 @@
+package firewall
+
+import "github.com/qdm12/golibs/command"
+
+type Runner interface {
+	Run(cmd command.ExecCmd) (output string, err error)
+}
+
+type Logger interface {
+	Debug(s string)
+	Info(s string)
+	Error(s string)
+}

internal/firewall/ip6tables.go

@@ -40,10 +40,14 @@ func (c *Config) runIP6tablesInstruction(ctx context.Context, instruction string
 	c.ip6tablesMutex.Lock() // only one ip6tables command at once
 	defer c.ip6tablesMutex.Unlock()
 
-	c.logger.Debug(c.ip6Tables + " " + instruction)
+	if isDeleteMatchInstruction(instruction) {
+		return deleteIPTablesRule(ctx, c.ip6Tables, instruction,
+			c.runner, c.logger)
+	}
 
 	flags := strings.Fields(instruction)
 	cmd := exec.CommandContext(ctx, c.ip6Tables, flags...) // #nosec G204
+	c.logger.Debug(cmd.String())
 	if output, err := c.runner.Run(cmd); err != nil {
 		return fmt.Errorf("command failed: \"%s %s\": %s: %w",
 			c.ip6Tables, instruction, output, err)
@@ -55,7 +59,7 @@ var ErrPolicyNotValid = errors.New("policy is not valid")
 
 func (c *Config) setIPv6AllPolicies(ctx context.Context, policy string) error {
 	switch policy {
-	case "ACCEPT", "DROP":
+	case "ACCEPT", "DROP": //nolint:goconst
 	default:
 		return fmt.Errorf("%w: %s", ErrPolicyNotValid, policy)
 	}

internal/firewall/iptables.go

@@ -70,10 +70,14 @@ func (c *Config) runIptablesInstruction(ctx context.Context, instruction string)
 	c.iptablesMutex.Lock() // only one iptables command at once
 	defer c.iptablesMutex.Unlock()
 
-	c.logger.Debug(c.ipTables + " " + instruction)
+	if isDeleteMatchInstruction(instruction) {
+		return deleteIPTablesRule(ctx, c.ipTables, instruction,
+			c.runner, c.logger)
+	}
 
 	flags := strings.Fields(instruction)
 	cmd := exec.CommandContext(ctx, c.ipTables, flags...) // #nosec G204
+	c.logger.Debug(cmd.String())
 	if output, err := c.runner.Run(cmd); err != nil {
 		return fmt.Errorf("command failed: \"%s %s\": %s: %w",
 			c.ipTables, instruction, output, err)
@@ -143,7 +147,7 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 	defaultInterface string, connection models.Connection, remove bool) error {
 	protocol := connection.Protocol
 	if protocol == "tcp-client" {
-		protocol = "tcp"
+		protocol = "tcp" //nolint:goconst
 	}
 	instruction := fmt.Sprintf("%s OUTPUT -d %s -o %s -p %s -m %s --dport %d -j ACCEPT",
 		appendOrDelete(remove), connection.IP, defaultInterface, protocol,

internal/firewall/list.go

@@ -0,0 +1,381 @@
+package firewall
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+type chain struct {
+	name    string
+	policy  string
+	packets uint64
+	bytes   uint64
+	rules   []chainRule
+}
+
+type chainRule struct {
+	lineNumber      uint16 // starts from 1 and cannot be zero.
+	packets         uint64
+	bytes           uint64
+	target          string       // "ACCEPT", "DROP", "REJECT" or "REDIRECT"
+	protocol        string       // "tcp", "udp" or "" for all protocols.
+	inputInterface  string       // input interface, for example "tun0" or "*""
+	outputInterface string       // output interface, for example "eth0" or "*""
+	source          netip.Prefix // source IP CIDR, for example 0.0.0.0/0. Must be valid.
+	destination     netip.Prefix // destination IP CIDR, for example 0.0.0.0/0. Must be valid.
+	destinationPort uint16       // Not specified if set to zero.
+	redirPorts      []uint16     // Not specified if empty.
+	ctstate         []string     // for example ["RELATED","ESTABLISHED"]. Can be empty.
+}
+
+var (
+	ErrChainListMalformed = errors.New("iptables chain list output is malformed")
+)
+
+func parseChain(iptablesOutput string) (c chain, err error) {
+	// Text example:
+	// Chain INPUT (policy ACCEPT 140K packets, 226M bytes)
+	// pkts bytes target     prot opt in     out     source               destination
+	// 	  0     0 ACCEPT     17   --  tun0   *       0.0.0.0/0            0.0.0.0/0            udp dpt:55405
+	// 	  0     0 ACCEPT     6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:55405
+	// 	  0     0 DROP       0    --  tun0   *       0.0.0.0/0            0.0.0.0/0
+	iptablesOutput = strings.TrimSpace(iptablesOutput)
+	linesWithComments := strings.Split(iptablesOutput, "\n")
+
+	// Filter out lines starting with a '#' character
+	lines := make([]string, 0, len(linesWithComments))
+	for _, line := range linesWithComments {
+		if strings.HasPrefix(line, "#") {
+			continue
+		}
+		lines = append(lines, line)
+	}
+
+	const minLines = 2 // chain general information line + legend line
+	if len(lines) < minLines {
+		return chain{}, fmt.Errorf("%w: not enough lines to process in: %s",
+			ErrChainListMalformed, iptablesOutput)
+	}
+
+	c, err = parseChainGeneralDataLine(lines[0])
+	if err != nil {
+		return chain{}, fmt.Errorf("parsing chain general data line: %w", err)
+	}
+
+	// Sanity check for the legend line
+	expectedLegendFields := []string{"num", "pkts", "bytes", "target", "prot", "opt", "in", "out", "source", "destination"}
+	legendLine := strings.TrimSpace(lines[1])
+	legendFields := strings.Fields(legendLine)
+	if !slices.Equal(expectedLegendFields, legendFields) {
+		return chain{}, fmt.Errorf("%w: legend %q is not the expected %q",
+			ErrChainListMalformed, legendLine, strings.Join(expectedLegendFields, " "))
+	}
+
+	lines = lines[2:] // remove chain general information line and legend line
+	if len(lines) == 0 {
+		return c, nil
+	}
+
+	c.rules = make([]chainRule, len(lines))
+	for i, line := range lines {
+		c.rules[i], err = parseChainRuleLine(line)
+		if err != nil {
+			return chain{}, fmt.Errorf("parsing chain rule %q: %w", line, err)
+		}
+	}
+
+	return c, nil
+}
+
+// parseChainGeneralDataLine parses the first line of iptables chain list output.
+// For example, it can parse the following line:
+// Chain INPUT (policy ACCEPT 140K packets, 226M bytes)
+// It returns a chain struct with the parsed data.
+func parseChainGeneralDataLine(line string) (base chain, err error) {
+	line = strings.TrimSpace(line)
+	runesToRemove := []rune{'(', ')', ','}
+	for _, r := range runesToRemove {
+		line = strings.ReplaceAll(line, string(r), "")
+	}
+
+	fields := strings.Fields(line)
+	const expectedNumberOfFields = 8
+	if len(fields) != expectedNumberOfFields {
+		return chain{}, fmt.Errorf("%w: expected %d fields in %q",
+			ErrChainListMalformed, expectedNumberOfFields, line)
+	}
+
+	// Sanity checks
+	indexToExpectedValue := map[int]string{
+		0: "Chain",
+		2: "policy",
+		5: "packets",
+		7: "bytes",
+	}
+	for index, expectedValue := range indexToExpectedValue {
+		if fields[index] == expectedValue {
+			continue
+		}
+		return chain{}, fmt.Errorf("%w: expected %q for field %d in %q",
+			ErrChainListMalformed, expectedValue, index, line)
+	}
+
+	base.name = fields[1] // chain name could be custom
+	base.policy = fields[3]
+	err = checkTarget(base.policy)
+	if err != nil {
+		return chain{}, fmt.Errorf("policy target in %q: %w", line, err)
+	}
+
+	packets, err := parseMetricSize(fields[4])
+	if err != nil {
+		return chain{}, fmt.Errorf("parsing packets: %w", err)
+	}
+	base.packets = packets
+
+	bytes, err := parseMetricSize(fields[6])
+	if err != nil {
+		return chain{}, fmt.Errorf("parsing bytes: %w", err)
+	}
+	base.bytes = bytes
+
+	return base, nil
+}
+
+var (
+	ErrChainRuleMalformed = errors.New("chain rule is malformed")
+)
+
+func parseChainRuleLine(line string) (rule chainRule, err error) {
+	line = strings.TrimSpace(line)
+	if line == "" {
+		return chainRule{}, fmt.Errorf("%w: empty line", ErrChainRuleMalformed)
+	}
+
+	fields := strings.Fields(line)
+
+	const minFields = 10
+	if len(fields) < minFields {
+		return chainRule{}, fmt.Errorf("%w: not enough fields", ErrChainRuleMalformed)
+	}
+
+	for fieldIndex, field := range fields[:minFields] {
+		err = parseChainRuleField(fieldIndex, field, &rule)
+		if err != nil {
+			return chainRule{}, fmt.Errorf("parsing chain rule field: %w", err)
+		}
+	}
+
+	if len(fields) > minFields {
+		err = parseChainRuleOptionalFields(fields[minFields:], &rule)
+		if err != nil {
+			return chainRule{}, fmt.Errorf("parsing optional fields: %w", err)
+		}
+	}
+
+	return rule, nil
+}
+
+func parseChainRuleField(fieldIndex int, field string, rule *chainRule) (err error) {
+	if field == "" {
+		return fmt.Errorf("%w: empty field at index %d", ErrChainRuleMalformed, fieldIndex)
+	}
+
+	const (
+		numIndex = iota
+		packetsIndex
+		bytesIndex
+		targetIndex
+		protocolIndex
+		optIndex
+		inputInterfaceIndex
+		outputInterfaceIndex
+		sourceIndex
+		destinationIndex
+	)
+
+	switch fieldIndex {
+	case numIndex:
+		rule.lineNumber, err = parseLineNumber(field)
+		if err != nil {
+			return fmt.Errorf("parsing line number: %w", err)
+		}
+	case packetsIndex:
+		rule.packets, err = parseMetricSize(field)
+		if err != nil {
+			return fmt.Errorf("parsing packets: %w", err)
+		}
+	case bytesIndex:
+		rule.bytes, err = parseMetricSize(field)
+		if err != nil {
+			return fmt.Errorf("parsing bytes: %w", err)
+		}
+	case targetIndex:
+		err = checkTarget(field)
+		if err != nil {
+			return fmt.Errorf("checking target: %w", err)
+		}
+		rule.target = field
+	case protocolIndex:
+		rule.protocol, err = parseProtocol(field)
+		if err != nil {
+			return fmt.Errorf("parsing protocol: %w", err)
+		}
+	case optIndex: // ignored
+	case inputInterfaceIndex:
+		rule.inputInterface = field
+	case outputInterfaceIndex:
+		rule.outputInterface = field
+	case sourceIndex:
+		rule.source, err = parseIPPrefix(field)
+		if err != nil {
+			return fmt.Errorf("parsing source IP CIDR: %w", err)
+		}
+	case destinationIndex:
+		rule.destination, err = parseIPPrefix(field)
+		if err != nil {
+			return fmt.Errorf("parsing destination IP CIDR: %w", err)
+		}
+	}
+	return nil
+}
+
+func parseChainRuleOptionalFields(optionalFields []string, rule *chainRule) (err error) {
+	for i := 0; i < len(optionalFields); i++ {
+		key := optionalFields[i]
+		switch key {
+		case "tcp", "udp":
+			i++
+			value := optionalFields[i]
+			value = strings.TrimPrefix(value, "dpt:")
+			const base, bitLength = 10, 16
+			destinationPort, err := strconv.ParseUint(value, base, bitLength)
+			if err != nil {
+				return fmt.Errorf("parsing destination port %q: %w", value, err)
+			}
+			rule.destinationPort = uint16(destinationPort)
+		case "redir":
+			i++
+			switch optionalFields[i] {
+			case "ports":
+				i++
+				ports, err := parsePortsCSV(optionalFields[i])
+				if err != nil {
+					return fmt.Errorf("parsing redirection ports: %w", err)
+				}
+				rule.redirPorts = ports
+			default:
+				return fmt.Errorf("%w: unexpected optional field: %s",
+					ErrChainRuleMalformed, optionalFields[i])
+			}
+		case "ctstate":
+			i++
+			rule.ctstate = strings.Split(optionalFields[i], ",")
+		default:
+			return fmt.Errorf("%w: unexpected optional field: %s", ErrChainRuleMalformed, key)
+		}
+	}
+	return nil
+}
+
+func parsePortsCSV(s string) (ports []uint16, err error) {
+	if s == "" {
+		return nil, nil
+	}
+
+	fields := strings.Split(s, ",")
+	ports = make([]uint16, len(fields))
+	for i, field := range fields {
+		const base, bitLength = 10, 16
+		port, err := strconv.ParseUint(field, base, bitLength)
+		if err != nil {
+			return nil, fmt.Errorf("parsing port %q: %w", field, err)
+		}
+		ports[i] = uint16(port)
+	}
+	return ports, nil
+}
+
+var (
+	ErrLineNumberIsZero = errors.New("line number is zero")
+)
+
+func parseLineNumber(s string) (n uint16, err error) {
+	const base, bitLength = 10, 16
+	lineNumber, err := strconv.ParseUint(s, base, bitLength)
+	if err != nil {
+		return 0, err
+	} else if lineNumber == 0 {
+		return 0, fmt.Errorf("%w", ErrLineNumberIsZero)
+	}
+	return uint16(lineNumber), nil
+}
+
+var (
+	ErrTargetUnknown = errors.New("unknown target")
+)
+
+func checkTarget(target string) (err error) {
+	switch target {
+	case "ACCEPT", "DROP", "REJECT", "REDIRECT":
+		return nil
+	}
+	return fmt.Errorf("%w: %s", ErrTargetUnknown, target)
+}
+
+var (
+	ErrProtocolUnknown = errors.New("unknown protocol")
+)
+
+func parseProtocol(s string) (protocol string, err error) {
+	switch s {
+	case "0":
+	case "6":
+		protocol = "tcp"
+	case "17":
+		protocol = "udp"
+	default:
+		return "", fmt.Errorf("%w: %s", ErrProtocolUnknown, s)
+	}
+	return protocol, nil
+}
+
+var (
+	ErrMetricSizeMalformed = errors.New("metric size is malformed")
+)
+
+// parseMetricSize parses a metric size string like 140K or 226M and
+// returns the raw integer matching it.
+func parseMetricSize(size string) (n uint64, err error) {
+	if size == "" {
+		return n, fmt.Errorf("%w: empty string", ErrMetricSizeMalformed)
+	}
+
+	//nolint:gomnd
+	multiplerLetterToValue := map[byte]uint64{
+		'K': 1000,
+		'M': 1000000,
+		'G': 1000000000,
+		'T': 1000000000000,
+	}
+
+	lastCharacter := size[len(size)-1]
+	multiplier, ok := multiplerLetterToValue[lastCharacter]
+	if ok { // multiplier present
+		size = size[:len(size)-1]
+	} else {
+		multiplier = 1
+	}
+
+	const base, bitLength = 10, 64
+	n, err = strconv.ParseUint(size, base, bitLength)
+	if err != nil {
+		return n, fmt.Errorf("%w: %w", ErrMetricSizeMalformed, err)
+	}
+	n *= multiplier
+	return n, nil
+}

internal/firewall/list_test.go

@@ -0,0 +1,121 @@
+package firewall
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_parseChain(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		iptablesOutput string
+		table          chain
+		errWrapped     error
+		errMessage     string
+	}{
+		"no_output": {
+			errWrapped: ErrChainListMalformed,
+			errMessage: "iptables chain list output is malformed: not enough lines to process in: ",
+		},
+		"single_line_only": {
+			iptablesOutput: `Chain INPUT (policy ACCEPT 140K packets, 226M bytes)`,
+			errWrapped:     ErrChainListMalformed,
+			errMessage: "iptables chain list output is malformed: not enough lines to process in: " +
+				"Chain INPUT (policy ACCEPT 140K packets, 226M bytes)",
+		},
+		"malformed_general_data_line": {
+			iptablesOutput: `Chain INPUT
+num pkts bytes target     prot opt in     out     source               destination`,
+			errWrapped: ErrChainListMalformed,
+			errMessage: "parsing chain general data line: iptables chain list output is malformed: " +
+				"expected 8 fields in \"Chain INPUT\"",
+		},
+		"malformed_legend": {
+			iptablesOutput: `Chain INPUT (policy ACCEPT 140K packets, 226M bytes)
+num pkts bytes target     prot opt in     out     source`,
+			errWrapped: ErrChainListMalformed,
+			errMessage: "iptables chain list output is malformed: legend " +
+				"\"num pkts bytes target     prot opt in     out     source\" " +
+				"is not the expected \"num pkts bytes target prot opt in out source destination\"",
+		},
+		"no_rule": {
+			iptablesOutput: `Chain INPUT (policy ACCEPT 140K packets, 226M bytes)
+num pkts bytes target     prot opt in     out     source               destination`,
+			table: chain{
+				name:    "INPUT",
+				policy:  "ACCEPT",
+				packets: 140000,
+				bytes:   226000000,
+			},
+		},
+		"some_rules": {
+			iptablesOutput: `Chain INPUT (policy ACCEPT 140K packets, 226M bytes)
+num pkts bytes target     prot opt in     out     source               destination
+1   0     0 ACCEPT     17   --  tun0   *       0.0.0.0/0            0.0.0.0/0            udp dpt:55405
+2   0     0 ACCEPT     6    --  tun0   *       0.0.0.0/0            0.0.0.0/0            tcp dpt:55405
+3   0     0 DROP       0    --  tun0   *       1.2.3.4              0.0.0.0/0
+`,
+			table: chain{
+				name:    "INPUT",
+				policy:  "ACCEPT",
+				packets: 140000,
+				bytes:   226000000,
+				rules: []chainRule{
+					{
+						lineNumber:      1,
+						packets:         0,
+						bytes:           0,
+						target:          "ACCEPT",
+						protocol:        "udp",
+						inputInterface:  "tun0",
+						outputInterface: "*",
+						source:          netip.MustParsePrefix("0.0.0.0/0"),
+						destination:     netip.MustParsePrefix("0.0.0.0/0"),
+						destinationPort: 55405,
+					},
+					{
+						lineNumber:      2,
+						packets:         0,
+						bytes:           0,
+						target:          "ACCEPT",
+						protocol:        "tcp",
+						inputInterface:  "tun0",
+						outputInterface: "*",
+						source:          netip.MustParsePrefix("0.0.0.0/0"),
+						destination:     netip.MustParsePrefix("0.0.0.0/0"),
+						destinationPort: 55405,
+					},
+					{
+						lineNumber:      3,
+						packets:         0,
+						bytes:           0,
+						target:          "DROP",
+						protocol:        "",
+						inputInterface:  "tun0",
+						outputInterface: "*",
+						source:          netip.MustParsePrefix("1.2.3.4/32"),
+						destination:     netip.MustParsePrefix("0.0.0.0/0"),
+					},
+				},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			table, err := parseChain(testCase.iptablesOutput)
+
+			assert.Equal(t, testCase.table, table)
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+		})
+	}
+}

internal/firewall/logger.go

@@ -5,12 +5,6 @@ import (
 	"net/netip"
 )
 
-type Logger interface {
-	Debug(s string)
-	Info(s string)
-	Error(s string)
-}
-
 func (c *Config) logIgnoredSubnetFamily(subnet netip.Prefix) {
 	c.logger.Info(fmt.Sprintf("ignoring subnet %s which has "+
 		"no default route matching its family", subnet))

internal/firewall/mocks_generate_test.go

@@ -0,0 +1,3 @@
+package firewall
+
+//go:generate mockgen -destination=mocks_test.go -package=$GOPACKAGE . Runner,Logger

internal/firewall/mocks_test.go

@@ -0,0 +1,109 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: github.com/qdm12/gluetun/internal/firewall (interfaces: Runner,Logger)
+
+// Package firewall is a generated GoMock package.
+package firewall
+
+import (
+	reflect "reflect"
+
+	gomock "github.com/golang/mock/gomock"
+	command "github.com/qdm12/golibs/command"
+)
+
+// MockRunner is a mock of Runner interface.
+type MockRunner struct {
+	ctrl     *gomock.Controller
+	recorder *MockRunnerMockRecorder
+}
+
+// MockRunnerMockRecorder is the mock recorder for MockRunner.
+type MockRunnerMockRecorder struct {
+	mock *MockRunner
+}
+
+// NewMockRunner creates a new mock instance.
+func NewMockRunner(ctrl *gomock.Controller) *MockRunner {
+	mock := &MockRunner{ctrl: ctrl}
+	mock.recorder = &MockRunnerMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockRunner) EXPECT() *MockRunnerMockRecorder {
+	return m.recorder
+}
+
+// Run mocks base method.
+func (m *MockRunner) Run(arg0 command.ExecCmd) (string, error) {
+	m.ctrl.T.Helper()
+	ret := m.ctrl.Call(m, "Run", arg0)
+	ret0, _ := ret[0].(string)
+	ret1, _ := ret[1].(error)
+	return ret0, ret1
+}
+
+// Run indicates an expected call of Run.
+func (mr *MockRunnerMockRecorder) Run(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Run", reflect.TypeOf((*MockRunner)(nil).Run), arg0)
+}
+
+// MockLogger is a mock of Logger interface.
+type MockLogger struct {
+	ctrl     *gomock.Controller
+	recorder *MockLoggerMockRecorder
+}
+
+// MockLoggerMockRecorder is the mock recorder for MockLogger.
+type MockLoggerMockRecorder struct {
+	mock *MockLogger
+}
+
+// NewMockLogger creates a new mock instance.
+func NewMockLogger(ctrl *gomock.Controller) *MockLogger {
+	mock := &MockLogger{ctrl: ctrl}
+	mock.recorder = &MockLoggerMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockLogger) EXPECT() *MockLoggerMockRecorder {
+	return m.recorder
+}
+
+// Debug mocks base method.
+func (m *MockLogger) Debug(arg0 string) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Debug", arg0)
+}
+
+// Debug indicates an expected call of Debug.
+func (mr *MockLoggerMockRecorder) Debug(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Debug", reflect.TypeOf((*MockLogger)(nil).Debug), arg0)
+}
+
+// Error mocks base method.
+func (m *MockLogger) Error(arg0 string) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Error", arg0)
+}
+
+// Error indicates an expected call of Error.
+func (mr *MockLoggerMockRecorder) Error(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Error", reflect.TypeOf((*MockLogger)(nil).Error), arg0)
+}
+
+// Info mocks base method.
+func (m *MockLogger) Info(arg0 string) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Info", arg0)
+}
+
+// Info indicates an expected call of Info.
+func (mr *MockLoggerMockRecorder) Info(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Info", reflect.TypeOf((*MockLogger)(nil).Info), arg0)
+}

internal/firewall/parse.go

@@ -0,0 +1,166 @@
+package firewall
+
+import (
+	"errors"
+	"fmt"
+	"net/netip"
+	"slices"
+	"strconv"
+	"strings"
+)
+
+type iptablesInstruction struct {
+	table           string // defaults to "filter", and can be "nat" for example.
+	append          bool
+	chain           string       // for example INPUT, PREROUTING. Cannot be empty.
+	target          string       // for example ACCEPT. Can be empty.
+	protocol        string       // "tcp" or "udp" or "" for all protocols.
+	inputInterface  string       // for example "tun0" or "" for any interface.
+	outputInterface string       // for example "tun0" or "" for any interface.
+	source          netip.Prefix // if not valid, then it is unspecified.
+	destination     netip.Prefix // if not valid, then it is unspecified.
+	destinationPort uint16       // if zero, there is no destination port
+	toPorts         []uint16     // if empty, there is no redirection
+	ctstate         []string     // if empty, there is no ctstate
+}
+
+func (i *iptablesInstruction) setDefaults() {
+	if i.table == "" {
+		i.table = "filter"
+	}
+}
+
+// equalToRule ignores the append boolean flag of the instruction to compare against the rule.
+func (i *iptablesInstruction) equalToRule(table, chain string, rule chainRule) (equal bool) {
+	switch {
+	case i.table != table:
+		return false
+	case i.chain != chain:
+		return false
+	case i.target != rule.target:
+		return false
+	case i.protocol != rule.protocol:
+		return false
+	case i.destinationPort != rule.destinationPort:
+		return false
+	case !slices.Equal(i.toPorts, rule.redirPorts):
+		return false
+	case !slices.Equal(i.ctstate, rule.ctstate):
+		return false
+	case !networkInterfacesEqual(i.inputInterface, rule.inputInterface):
+		return false
+	case !networkInterfacesEqual(i.outputInterface, rule.outputInterface):
+		return false
+	case !ipPrefixesEqual(i.source, rule.source):
+		return false
+	case !ipPrefixesEqual(i.destination, rule.destination):
+		return false
+	default:
+		return true
+	}
+}
+
+// instruction can be "" which equivalent to the "*" chain rule interface.
+func networkInterfacesEqual(instruction, chainRule string) bool {
+	return instruction == chainRule || (instruction == "" && chainRule == "*")
+}
+
+func ipPrefixesEqual(instruction, chainRule netip.Prefix) bool {
+	return instruction == chainRule ||
+		(!instruction.IsValid() && chainRule.Bits() == 0 && chainRule.Addr().IsUnspecified())
+}
+
+var (
+	ErrIptablesCommandMalformed = errors.New("iptables command is malformed")
+)
+
+func parseIptablesInstruction(s string) (instruction iptablesInstruction, err error) {
+	if s == "" {
+		return iptablesInstruction{}, fmt.Errorf("%w: empty instruction", ErrIptablesCommandMalformed)
+	}
+	fields := strings.Fields(s)
+	if len(fields)%2 != 0 {
+		return iptablesInstruction{}, fmt.Errorf("%w: fields count %d is not even: %q",
+			ErrIptablesCommandMalformed, len(fields), s)
+	}
+
+	for i := 0; i < len(fields); i += 2 {
+		key := fields[i]
+		value := fields[i+1]
+		err = parseInstructionFlag(key, value, &instruction)
+		if err != nil {
+			return iptablesInstruction{}, fmt.Errorf("parsing %q: %w", s, err)
+		}
+	}
+
+	instruction.setDefaults()
+	return instruction, nil
+}
+
+func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (err error) {
+	switch key {
+	case "-t", "--table":
+		instruction.table = value
+	case "-D", "--delete":
+		instruction.append = false
+		instruction.chain = value
+	case "-A", "--append":
+		instruction.append = true
+		instruction.chain = value
+	case "-j", "--jump":
+		instruction.target = value
+	case "-p", "--protocol":
+		instruction.protocol = value
+	case "-m", "--match": // ignore match
+	case "-i", "--in-interface":
+		instruction.inputInterface = value
+	case "-o", "--out-interface":
+		instruction.outputInterface = value
+	case "-s", "--source":
+		instruction.source, err = parseIPPrefix(value)
+		if err != nil {
+			return fmt.Errorf("parsing source IP CIDR: %w", err)
+		}
+	case "-d", "--destination":
+		instruction.destination, err = parseIPPrefix(value)
+		if err != nil {
+			return fmt.Errorf("parsing destination IP CIDR: %w", err)
+		}
+	case "--dport":
+		const base, bitLength = 10, 16
+		destinationPort, err := strconv.ParseUint(value, base, bitLength)
+		if err != nil {
+			return fmt.Errorf("parsing destination port: %w", err)
+		}
+		instruction.destinationPort = uint16(destinationPort)
+	case "--ctstate":
+		instruction.ctstate = strings.Split(value, ",")
+	case "--to-ports":
+		portStrings := strings.Split(value, ",")
+		instruction.toPorts = make([]uint16, len(portStrings))
+		for i, portString := range portStrings {
+			const base, bitLength = 10, 16
+			port, err := strconv.ParseUint(portString, base, bitLength)
+			if err != nil {
+				return fmt.Errorf("parsing port redirection: %w", err)
+			}
+			instruction.toPorts[i] = uint16(port)
+		}
+	default:
+		return fmt.Errorf("%w: unknown key %q", ErrIptablesCommandMalformed, key)
+	}
+	return nil
+}
+
+func parseIPPrefix(value string) (prefix netip.Prefix, err error) {
+	slashIndex := strings.Index(value, "/")
+	if slashIndex >= 0 {
+		return netip.ParsePrefix(value)
+	}
+
+	ip, err := netip.ParseAddr(value)
+	if err != nil {
+		return netip.Prefix{}, fmt.Errorf("parsing IP address: %w", err)
+	}
+	return netip.PrefixFrom(ip, ip.BitLen()), nil
+}

internal/firewall/parse_test.go

@@ -0,0 +1,138 @@
+package firewall
+
+import (
+	"net/netip"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_parseIptablesInstruction(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		s           string
+		instruction iptablesInstruction
+		errWrapped  error
+		errMessage  string
+	}{
+		"no_instruction": {
+			errWrapped: ErrIptablesCommandMalformed,
+			errMessage: "iptables command is malformed: empty instruction",
+		},
+		"uneven_fields": {
+			s:          "-A",
+			errWrapped: ErrIptablesCommandMalformed,
+			errMessage: "iptables command is malformed: fields count 1 is not even: \"-A\"",
+		},
+		"unknown_key": {
+			s:          "-x something",
+			errWrapped: ErrIptablesCommandMalformed,
+			errMessage: "parsing \"-x something\": iptables command is malformed: unknown key \"-x\"",
+		},
+		"one_pair": {
+			s: "-A INPUT",
+			instruction: iptablesInstruction{
+				table:  "filter",
+				chain:  "INPUT",
+				append: true,
+			},
+		},
+		"instruction_A": {
+			s: "-A INPUT -i tun0 -p tcp -m tcp -s 1.2.3.4/32 -d 5.6.7.8 --dport 10000 -j ACCEPT",
+			instruction: iptablesInstruction{
+				table:           "filter",
+				chain:           "INPUT",
+				append:          true,
+				inputInterface:  "tun0",
+				protocol:        "tcp",
+				source:          netip.MustParsePrefix("1.2.3.4/32"),
+				destination:     netip.MustParsePrefix("5.6.7.8/32"),
+				destinationPort: 10000,
+				target:          "ACCEPT",
+			},
+		},
+		"nat_redirection": {
+			s: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",
+			instruction: iptablesInstruction{
+				table:           "nat",
+				chain:           "PREROUTING",
+				append:          false,
+				inputInterface:  "tun0",
+				protocol:        "tcp",
+				destinationPort: 43716,
+				target:          "REDIRECT",
+				toPorts:         []uint16{5678},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			rule, err := parseIptablesInstruction(testCase.s)
+
+			assert.Equal(t, testCase.instruction, rule)
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+		})
+	}
+}
+
+func Test_parseIPPrefix(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		value      string
+		prefix     netip.Prefix
+		errMessage string
+	}{
+		"empty": {
+			errMessage: `parsing IP address: ParseAddr(""): unable to parse IP`,
+		},
+		"invalid": {
+			value:      "invalid",
+			errMessage: `parsing IP address: ParseAddr("invalid"): unable to parse IP`,
+		},
+		"valid_ipv4_with_bits": {
+			value:  "10.0.0.0/16",
+			prefix: netip.PrefixFrom(netip.AddrFrom4([4]byte{10, 0, 0, 0}), 16),
+		},
+		"valid_ipv4_without_bits": {
+			value:  "10.0.0.4",
+			prefix: netip.PrefixFrom(netip.AddrFrom4([4]byte{10, 0, 0, 4}), 32),
+		},
+		"valid_ipv6_with_bits": {
+			value: "2001:db8::/32",
+			prefix: netip.PrefixFrom(
+				netip.AddrFrom16([16]byte{0x20, 0x01, 0x0d, 0xb8}),
+				32),
+		},
+		"valid_ipv6_without_bits": {
+			value: "2001:db8::",
+			prefix: netip.PrefixFrom(
+				netip.AddrFrom16([16]byte{0x20, 0x01, 0x0d, 0xb8}),
+				128),
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			prefix, err := parseIPPrefix(testCase.value)
+
+			assert.Equal(t, testCase.prefix, prefix)
+			if testCase.errMessage != "" {
+				assert.EqualError(t, err, testCase.errMessage)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}

internal/firewall/runner_mock_test.go

@@ -1,50 +0,0 @@
-// Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/qdm12/golibs/command (interfaces: Runner)
-
-// Package firewall is a generated GoMock package.
-package firewall
-
-import (
-	reflect "reflect"
-
-	gomock "github.com/golang/mock/gomock"
-	command "github.com/qdm12/golibs/command"
-)
-
-// MockRunner is a mock of Runner interface.
-type MockRunner struct {
-	ctrl     *gomock.Controller
-	recorder *MockRunnerMockRecorder
-}
-
-// MockRunnerMockRecorder is the mock recorder for MockRunner.
-type MockRunnerMockRecorder struct {
-	mock *MockRunner
-}
-
-// NewMockRunner creates a new mock instance.
-func NewMockRunner(ctrl *gomock.Controller) *MockRunner {
-	mock := &MockRunner{ctrl: ctrl}
-	mock.recorder = &MockRunnerMockRecorder{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use.
-func (m *MockRunner) EXPECT() *MockRunnerMockRecorder {
-	return m.recorder
-}
-
-// Run mocks base method.
-func (m *MockRunner) Run(arg0 command.ExecCmd) (string, error) {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "Run", arg0)
-	ret0, _ := ret[0].(string)
-	ret1, _ := ret[1].(error)
-	return ret0, ret1
-}
-
-// Run indicates an expected call of Run.
-func (mr *MockRunnerMockRecorder) Run(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Run", reflect.TypeOf((*MockRunner)(nil).Run), arg0)
-}

internal/firewall/support_test.go

@@ -11,8 +11,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-//go:generate mockgen -destination=runner_mock_test.go -package $GOPACKAGE github.com/qdm12/golibs/command Runner
-
 func newAppendTestRuleMatcher(path string) *cmdMatcher {
 	return newCmdMatcher(path,
 		"^-A$", "^OUTPUT$", "^-o$", "^[a-z0-9]{15}$",

internal/provider/ivpn/updater/servers.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"sort"
+	"strings"
 
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
@@ -58,9 +59,11 @@ func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 
 	servers = make([]models.Server, 0, len(hostToIPs))
 	for _, serverData := range data.Servers {
+		city, region := parseCity(serverData.City)
 		server := models.Server{
 			Country: serverData.Country,
-			City:    serverData.City,
+			City:    city,
+			Region:  region,
 			ISP:     serverData.ISP,
 		}
 
@@ -96,3 +99,11 @@ func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 
 	return servers, nil
 }
+
+func parseCity(city string) (parsedCity, region string) {
+	commaIndex := strings.Index(city, ", ")
+	if commaIndex == -1 {
+		return city, ""
+	}
+	return city[:commaIndex], city[commaIndex+2:]
+}

internal/provider/nordvpn/updater/models.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"net/netip"
+	"strings"
 )
 
 // Check out the JSON data from https://api.nordvpn.com/v2/servers?limit=10
@@ -92,6 +93,9 @@ func (s serversData) idToData() (
 ) {
 	groups = make(map[uint32]groupData, len(s.Groups))
 	for _, group := range s.Groups {
+		if group.Type.Identifier == "regions" { //nolint:goconst
+			group.Title = strings.ReplaceAll(group.Title, ",", "")
+		}
 		groups[group.ID] = group
 	}
 

internal/provider/nordvpn/updater/servers.go

@@ -79,7 +79,7 @@ func extractServers(jsonServer serverData, groups map[uint32]groupData,
 
 	server := models.Server{
 		Country:    location.Country.Name,
-		Region:     jsonServer.region(groups),
+		Region:     region,
 		City:       location.Country.City.Name,
 		Categories: jsonServer.categories(groups),
 		Hostname:   jsonServer.Hostname,

internal/provider/privateinternetaccess/portforward.go

@@ -39,7 +39,7 @@ func (p *Provider) PortForward(ctx context.Context,
 	}
 
 	serverName := objects.ServerName
-
+	apiIP := buildAPIIPAddress(objects.Gateway)
 	logger := objects.Logger
 
 	if !objects.CanPortForward {
@@ -70,7 +70,7 @@ func (p *Provider) PortForward(ctx context.Context,
 
 	if !dataFound || expired {
 		client := objects.Client
-		data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, objects.Gateway,
+		data, err = refreshPIAPortForwardData(ctx, client, privateIPClient, apiIP,
 			p.portForwardPath, objects.Username, objects.Password)
 		if err != nil {
 			return nil, fmt.Errorf("refreshing port forward data: %w", err)
@@ -80,7 +80,7 @@ func (p *Provider) PortForward(ctx context.Context,
 	logger.Info("Port forwarded data expires in " + format.FriendlyDuration(durationToExpiration))
 
 	// First time binding
-	if err := bindPort(ctx, privateIPClient, objects.Gateway, data); err != nil {
+	if err := bindPort(ctx, privateIPClient, apiIP, data); err != nil {
 		return nil, fmt.Errorf("binding port: %w", err)
 	}
 
@@ -100,6 +100,8 @@ func (p *Provider) KeepPortForward(ctx context.Context,
 		panic("gateway is not set")
 	}
 
+	apiIP := buildAPIIPAddress(objects.Gateway)
+
 	privateIPClient, err := newHTTPClient(objects.ServerName)
 	if err != nil {
 		return fmt.Errorf("creating custom HTTP client: %w", err)
@@ -127,7 +129,7 @@ func (p *Provider) KeepPortForward(ctx context.Context,
 			}
 			return ctx.Err()
 		case <-keepAliveTimer.C:
-			err = bindPort(ctx, privateIPClient, objects.Gateway, data)
+			err = bindPort(ctx, privateIPClient, apiIP, data)
 			if err != nil {
 				return fmt.Errorf("binding port: %w", err)
 			}
@@ -139,14 +141,25 @@ func (p *Provider) KeepPortForward(ctx context.Context,
 	}
 }
 
+func buildAPIIPAddress(gateway netip.Addr) (api netip.Addr) {
+	if gateway.Is6() {
+		panic("IPv6 gateway not supported")
+	}
+
+	gatewayBytes := gateway.As4()
+	gatewayBytes[2] = 128
+	gatewayBytes[3] = 1
+	return netip.AddrFrom4(gatewayBytes)
+}
+
 func refreshPIAPortForwardData(ctx context.Context, client, privateIPClient *http.Client,
-	gateway netip.Addr, portForwardPath, username, password string) (data piaPortForwardData, err error) {
+	apiIP netip.Addr, portForwardPath, username, password string) (data piaPortForwardData, err error) {
 	data.Token, err = fetchToken(ctx, client, username, password)
 	if err != nil {
 		return data, fmt.Errorf("fetching token: %w", err)
 	}
 
-	data.Port, data.Signature, data.Expiration, err = fetchPortForwardData(ctx, privateIPClient, gateway, data.Token)
+	data.Port, data.Signature, data.Expiration, err = fetchPortForwardData(ctx, privateIPClient, apiIP, data.Token)
 	if err != nil {
 		return data, fmt.Errorf("fetching port forwarding data: %w", err)
 	}
@@ -286,7 +299,7 @@ func fetchToken(ctx context.Context, client *http.Client,
 	return result.Token, nil
 }
 
-func fetchPortForwardData(ctx context.Context, client *http.Client, gateway netip.Addr, token string) (
+func fetchPortForwardData(ctx context.Context, client *http.Client, apiIP netip.Addr, token string) (
 	port uint16, signature string, expiration time.Time, err error) {
 	errSubstitutions := map[string]string{url.QueryEscape(token): "<token>"}
 
@@ -294,7 +307,7 @@ func fetchPortForwardData(ctx context.Context, client *http.Client, gateway neti
 	queryParams.Add("token", token)
 	url := url.URL{
 		Scheme:   "https",
-		Host:     net.JoinHostPort(gateway.String(), "19999"),
+		Host:     net.JoinHostPort(apiIP.String(), "19999"),
 		Path:     "/getSignature",
 		RawQuery: queryParams.Encode(),
 	}
@@ -340,7 +353,7 @@ var (
 	ErrBadResponse = errors.New("bad response received")
 )
 
-func bindPort(ctx context.Context, client *http.Client, gateway netip.Addr, data piaPortForwardData) (err error) {
+func bindPort(ctx context.Context, client *http.Client, apiIPAddress netip.Addr, data piaPortForwardData) (err error) {
 	payload, err := packPayload(data.Port, data.Token, data.Expiration)
 	if err != nil {
 		return fmt.Errorf("serializing payload: %w", err)
@@ -351,7 +364,7 @@ func bindPort(ctx context.Context, client *http.Client, gateway netip.Addr, data
 	queryParams.Add("signature", data.Signature)
 	bindPortURL := url.URL{
 		Scheme:   "https",
-		Host:     net.JoinHostPort(gateway.String(), "19999"),
+		Host:     net.JoinHostPort(apiIPAddress.String(), "19999"),
 		Path:     "/bindPort",
 		RawQuery: queryParams.Encode(),
 	}

internal/server/handler.go

@@ -2,13 +2,17 @@ package server
 
 import (
 	"context"
+	"fmt"
 	"net/http"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/server/middlewares/auth"
+	"github.com/qdm12/gluetun/internal/server/middlewares/log"
 )
 
-func newHandler(ctx context.Context, logger infoWarner, logging bool,
+func newHandler(ctx context.Context, logger Logger, logging bool,
+	authSettings auth.Settings,
 	buildInfo models.BuildInformation,
 	vpnLooper VPNLooper,
 	pfGetter PortForwardedGetter,
@@ -17,7 +21,7 @@ func newHandler(ctx context.Context, logger infoWarner, logging bool,
 	publicIPLooper PublicIPLoop,
 	storage Storage,
 	ipv6Supported bool,
-) http.Handler {
+) (httpHandler http.Handler, err error) {
 	handler := &handler{}
 
 	vpn := newVPNHandler(ctx, vpnLooper, storage, ipv6Supported, logger)
@@ -29,16 +33,25 @@ func newHandler(ctx context.Context, logger infoWarner, logging bool,
 	handler.v0 = newHandlerV0(ctx, logger, vpnLooper, unboundLooper, updaterLooper)
 	handler.v1 = newHandlerV1(logger, buildInfo, vpn, openvpn, dns, updater, publicip)
 
-	handlerWithLog := withLogMiddleware(handler, logger, logging)
+	authMiddleware, err := auth.New(authSettings, logger)
-	handler.setLogEnabled = handlerWithLog.setEnabled
+	if err != nil {
+		return nil, fmt.Errorf("creating auth middleware: %w", err)
+	}
 
-	return handlerWithLog
+	middlewares := []func(http.Handler) http.Handler{
+		authMiddleware,
+		log.New(logger, logging),
+	}
+	httpHandler = handler
+	for _, middleware := range middlewares {
+		httpHandler = middleware(httpHandler)
+	}
+	return httpHandler, nil
 }
 
 type handler struct {
-	v0            http.Handler
+	v0 http.Handler
-	v1            http.Handler
+	v1 http.Handler
-	setLogEnabled func(enabled bool)
 }
 
 func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {

internal/server/logger.go

@@ -1,8 +1,10 @@
 package server
 
 type Logger interface {
+	Debugf(format string, args ...any)
 	infoer
 	warner
+	Warnf(format string, args ...any)
 	errorer
 }
 

internal/server/middlewares/auth/apikey.go

@@ -0,0 +1,36 @@
+package auth
+
+import (
+	"crypto/sha256"
+	"crypto/subtle"
+	"net/http"
+)
+
+type apiKeyMethod struct {
+	apiKeyDigest [32]byte
+}
+
+func newAPIKeyMethod(apiKey string) *apiKeyMethod {
+	return &apiKeyMethod{
+		apiKeyDigest: sha256.Sum256([]byte(apiKey)),
+	}
+}
+
+// equal returns true if another auth checker is equal.
+// This is used to deduplicate checkers for a particular route.
+func (a *apiKeyMethod) equal(other authorizationChecker) bool {
+	otherTokenMethod, ok := other.(*apiKeyMethod)
+	if !ok {
+		return false
+	}
+	return a.apiKeyDigest == otherTokenMethod.apiKeyDigest
+}
+
+func (a *apiKeyMethod) isAuthorized(_ http.Header, request *http.Request) bool {
+	xAPIKey := request.Header.Get("X-API-Key")
+	if xAPIKey == "" {
+		xAPIKey = request.URL.Query().Get("api_key")
+	}
+	xAPIKeyDigest := sha256.Sum256([]byte(xAPIKey))
+	return subtle.ConstantTimeCompare(xAPIKeyDigest[:], a.apiKeyDigest[:]) == 1
+}

internal/server/middlewares/auth/basic.go

@@ -0,0 +1,37 @@
+package auth
+
+import (
+	"crypto/sha256"
+	"crypto/subtle"
+	"net/http"
+)
+
+type basicAuthMethod struct {
+	authDigest [32]byte
+}
+
+func newBasicAuthMethod(username, password string) *basicAuthMethod {
+	return &basicAuthMethod{
+		authDigest: sha256.Sum256([]byte(username + password)),
+	}
+}
+
+// equal returns true if another auth checker is equal.
+// This is used to deduplicate checkers for a particular route.
+func (a *basicAuthMethod) equal(other authorizationChecker) bool {
+	otherBasicMethod, ok := other.(*basicAuthMethod)
+	if !ok {
+		return false
+	}
+	return a.authDigest == otherBasicMethod.authDigest
+}
+
+func (a *basicAuthMethod) isAuthorized(headers http.Header, request *http.Request) bool {
+	username, password, ok := request.BasicAuth()
+	if !ok {
+		headers.Set("WWW-Authenticate", `Basic realm="restricted", charset="UTF-8"`)
+		return false
+	}
+	requestAuthDigest := sha256.Sum256([]byte(username + password))
+	return subtle.ConstantTimeCompare(a.authDigest[:], requestAuthDigest[:]) == 1
+}

internal/server/middlewares/auth/configfile.go

@@ -0,0 +1,35 @@
+package auth
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/pelletier/go-toml/v2"
+)
+
+// Read reads the toml file specified by the filepath given.
+// If the file does not exist, it returns empty settings and no error.
+func Read(filepath string) (settings Settings, err error) {
+	file, err := os.Open(filepath)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return Settings{}, nil
+		}
+		return settings, fmt.Errorf("opening file: %w", err)
+	}
+	decoder := toml.NewDecoder(file)
+	decoder.DisallowUnknownFields()
+	err = decoder.Decode(&settings)
+	if err == nil {
+		return settings, nil
+	}
+
+	strictErr := new(toml.StrictMissingError)
+	ok := errors.As(err, &strictErr)
+	if !ok {
+		return settings, fmt.Errorf("toml decoding file: %w", err)
+	}
+	return settings, fmt.Errorf("toml decoding file: %w:\n%s",
+		strictErr, strictErr.String())
+}

internal/server/middlewares/auth/configfile_test.go

@@ -0,0 +1,80 @@
+package auth
+
+import (
+	"io/fs"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// Read reads the toml file specified by the filepath given.
+func Test_Read(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		fileContent string
+		settings    Settings
+		errMessage  string
+	}{
+		"empty_file": {},
+		"malformed_toml": {
+			fileContent: "this is not a toml file",
+			errMessage:  `toml decoding file: toml: expected character =`,
+		},
+		"unknown_field": {
+			fileContent: `unknown = "what is this"`,
+			errMessage: `toml decoding file: strict mode: fields in the document are missing in the target struct:
+1| unknown = "what is this"
+ | ~~~~~~~ missing field`,
+		},
+		"filled_settings": {
+			fileContent: `[[roles]]
+name = "public"
+auth = "none"
+routes = ["GET /v1/vpn/status", "PUT /v1/vpn/status"]
+
+[[roles]]
+name = "client"
+auth = "apikey"
+apikey = "xyz"
+routes = ["GET /v1/vpn/status"]
+`,
+			settings: Settings{
+				Roles: []Role{{
+					Name:   "public",
+					Auth:   AuthNone,
+					Routes: []string{"GET /v1/vpn/status", "PUT /v1/vpn/status"},
+				}, {
+					Name:   "client",
+					Auth:   AuthAPIKey,
+					APIKey: "xyz",
+					Routes: []string{"GET /v1/vpn/status"},
+				}},
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			tempDir := t.TempDir()
+			filepath := tempDir + "/config.toml"
+			const permissions fs.FileMode = 0600
+			err := os.WriteFile(filepath, []byte(testCase.fileContent), permissions)
+			require.NoError(t, err)
+
+			settings, err := Read(filepath)
+
+			assert.Equal(t, testCase.settings, settings)
+			if testCase.errMessage != "" {
+				assert.EqualError(t, err, testCase.errMessage)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}

internal/server/middlewares/auth/format.go

@@ -0,0 +1,22 @@
+package auth
+
+func andStrings(strings []string) (result string) {
+	return joinStrings(strings, "and")
+}
+
+func joinStrings(strings []string, lastJoin string) (result string) {
+	if len(strings) == 0 {
+		return ""
+	}
+
+	result = strings[0]
+	for i := 1; i < len(strings); i++ {
+		if i < len(strings)-1 {
+			result += ", " + strings[i]
+		} else {
+			result += " " + lastJoin + " " + strings[i]
+		}
+	}
+
+	return result
+}

internal/server/middlewares/auth/interfaces.go

@@ -0,0 +1,6 @@
+package auth
+
+type DebugLogger interface {
+	Debugf(format string, args ...any)
+	Warnf(format string, args ...any)
+}

internal/server/middlewares/auth/interfaces_local.go

@@ -0,0 +1,8 @@
+package auth
+
+import "net/http"
+
+type authorizationChecker interface {
+	equal(other authorizationChecker) bool
+	isAuthorized(headers http.Header, request *http.Request) bool
+}

internal/server/middlewares/auth/lookup.go

@@ -0,0 +1,47 @@
+package auth
+
+import (
+	"fmt"
+)
+
+type internalRole struct {
+	name    string
+	checker authorizationChecker
+}
+
+func settingsToLookupMap(settings Settings) (routeToRoles map[string][]internalRole, err error) {
+	routeToRoles = make(map[string][]internalRole)
+	for _, role := range settings.Roles {
+		var checker authorizationChecker
+		switch role.Auth {
+		case AuthNone:
+			checker = newNoneMethod()
+		case AuthAPIKey:
+			checker = newAPIKeyMethod(role.APIKey)
+		case AuthBasic:
+			checker = newBasicAuthMethod(role.Username, role.Password)
+		default:
+			return nil, fmt.Errorf("%w: %s", ErrMethodNotSupported, role.Auth)
+		}
+
+		iRole := internalRole{
+			name:    role.Name,
+			checker: checker,
+		}
+		for _, route := range role.Routes {
+			checkerExists := false
+			for _, role := range routeToRoles[route] {
+				if role.checker.equal(iRole.checker) {
+					checkerExists = true
+					break
+				}
+			}
+			if checkerExists {
+				// even if the role name is different, if the checker is the same, skip it.
+				continue
+			}
+			routeToRoles[route] = append(routeToRoles[route], iRole)
+		}
+	}
+	return routeToRoles, nil
+}

internal/server/middlewares/auth/lookup_test.go

@@ -0,0 +1,60 @@
+package auth
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// Read reads the toml file specified by the filepath given.
+func Test_settingsToLookupMap(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		settings     Settings
+		routeToRoles map[string][]internalRole
+		errWrapped   error
+		errMessage   string
+	}{
+		"empty_settings": {
+			routeToRoles: map[string][]internalRole{},
+		},
+		"auth_method_not_supported": {
+			settings: Settings{
+				Roles: []Role{{Name: "a", Auth: "bad"}},
+			},
+			errWrapped: ErrMethodNotSupported,
+			errMessage: "authentication method not supported: bad",
+		},
+		"success": {
+			settings: Settings{
+				Roles: []Role{
+					{Name: "a", Auth: AuthNone, Routes: []string{"GET /path"}},
+					{Name: "b", Auth: AuthNone, Routes: []string{"GET /path", "PUT /path"}},
+				},
+			},
+			routeToRoles: map[string][]internalRole{
+				"GET /path": {
+					{name: "a", checker: newNoneMethod()}, // deduplicated method
+				},
+				"PUT /path": {
+					{name: "b", checker: newNoneMethod()},
+				}},
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			routeToRoles, err := settingsToLookupMap(testCase.settings)
+
+			assert.Equal(t, testCase.routeToRoles, routeToRoles)
+			assert.ErrorIs(t, err, testCase.errWrapped)
+			if testCase.errWrapped != nil {
+				assert.EqualError(t, err, testCase.errMessage)
+			}
+		})
+	}
+}

internal/server/middlewares/auth/middleware.go

@@ -0,0 +1,111 @@
+package auth
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func New(settings Settings, debugLogger DebugLogger) (
+	middleware func(http.Handler) http.Handler,
+	err error) {
+	routeToRoles, err := settingsToLookupMap(settings)
+	if err != nil {
+		return nil, fmt.Errorf("converting settings to lookup maps: %w", err)
+	}
+
+	//nolint:goconst
+	return func(handler http.Handler) http.Handler {
+		return &authHandler{
+			childHandler: handler,
+			routeToRoles: routeToRoles,
+			unprotectedRoutes: map[string]struct{}{
+				http.MethodGet + " /openvpn/actions/restart": {},
+				http.MethodGet + " /unbound/actions/restart": {},
+				http.MethodGet + " /updater/restart":         {},
+				http.MethodGet + " /v1/version":              {},
+				http.MethodGet + " /v1/vpn/status":           {},
+				http.MethodPut + " /v1/vpn/status":           {},
+				// GET /v1/vpn/settings is protected by default
+				// PUT /v1/vpn/settings is protected by default
+				http.MethodGet + " /v1/openvpn/status":        {},
+				http.MethodPut + " /v1/openvpn/status":        {},
+				http.MethodGet + " /v1/openvpn/portforwarded": {},
+				// GET /v1/openvpn/settings is protected by default
+				http.MethodGet + " /v1/dns/status":     {},
+				http.MethodPut + " /v1/dns/status":     {},
+				http.MethodGet + " /v1/updater/status": {},
+				http.MethodPut + " /v1/updater/status": {},
+				http.MethodGet + " /v1/publicip/ip":    {},
+			},
+			logger: debugLogger,
+		}
+	}, nil
+}
+
+type authHandler struct {
+	childHandler      http.Handler
+	routeToRoles      map[string][]internalRole
+	unprotectedRoutes map[string]struct{} // TODO v3.41.0 remove
+	logger            DebugLogger
+}
+
+func (h *authHandler) ServeHTTP(writer http.ResponseWriter, request *http.Request) {
+	route := request.Method + " " + request.URL.Path
+	roles := h.routeToRoles[route]
+	if len(roles) == 0 {
+		h.logger.Debugf("no authentication role defined for route %s", route)
+		http.Error(writer, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
+		return
+	}
+
+	responseHeader := make(http.Header, 0)
+	for _, role := range roles {
+		if !role.checker.isAuthorized(responseHeader, request) {
+			continue
+		}
+
+		h.warnIfUnprotectedByDefault(role, route) // TODO v3.41.0 remove
+
+		h.logger.Debugf("access to route %s authorized for role %s", route, role.name)
+		h.childHandler.ServeHTTP(writer, request)
+		return
+	}
+
+	// Flush out response headers if all roles failed to authenticate
+	for headerKey, headerValues := range responseHeader {
+		for _, headerValue := range headerValues {
+			writer.Header().Add(headerKey, headerValue)
+		}
+	}
+
+	allRoleNames := make([]string, len(roles))
+	for i, role := range roles {
+		allRoleNames[i] = role.name
+	}
+	h.logger.Debugf("access to route %s unauthorized after checking for roles %s",
+		route, andStrings(allRoleNames))
+	http.Error(writer, http.StatusText(http.StatusUnauthorized), http.StatusUnauthorized)
+}
+
+func (h *authHandler) warnIfUnprotectedByDefault(role internalRole, route string) {
+	// TODO v3.41.0 remove
+	if role.name != "public" {
+		// custom role name, allow none authentication to be specified
+		return
+	}
+	_, isNoneChecker := role.checker.(*noneMethod)
+	if !isNoneChecker {
+		// not the none authentication method
+		return
+	}
+	_, isUnprotectedByDefault := h.unprotectedRoutes[route]
+	if !isUnprotectedByDefault {
+		// route is not unprotected by default, so this is a user decision
+		return
+	}
+	h.logger.Warnf("route %s is unprotected by default, "+
+		"please set up authentication following the documentation at "+
+		"https://github.com/qdm12/gluetun-wiki/setup/advanced/control-server.md#authentication "+
+		"since this will become no longer publicly accessible after release v3.40.",
+		route)
+}

internal/server/middlewares/auth/middleware_test.go

@@ -0,0 +1,124 @@
+package auth
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_authHandler_ServeHTTP(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		settings      Settings
+		makeLogger    func(ctrl *gomock.Controller) *MockDebugLogger
+		requestMethod string
+		requestPath   string
+		statusCode    int
+		responseBody  string
+	}{
+		"route_has_no_role": {
+			settings: Settings{
+				Roles: []Role{
+					{Name: "role1", Auth: AuthNone, Routes: []string{"GET /a"}},
+				},
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockDebugLogger {
+				logger := NewMockDebugLogger(ctrl)
+				logger.EXPECT().Debugf("no authentication role defined for route %s", "GET /b")
+				return logger
+			},
+			requestMethod: http.MethodGet,
+			requestPath:   "/b",
+			statusCode:    http.StatusUnauthorized,
+			responseBody:  "Unauthorized\n",
+		},
+		"authorized_unprotected_by_default": {
+			settings: Settings{
+				Roles: []Role{
+					{Name: "public", Auth: AuthNone, Routes: []string{"GET /v1/vpn/status"}},
+				},
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockDebugLogger {
+				logger := NewMockDebugLogger(ctrl)
+				logger.EXPECT().Warnf("route %s is unprotected by default, "+
+					"please set up authentication following the documentation at "+
+					"https://github.com/qdm12/gluetun-wiki/setup/advanced/control-server.md#authentication "+
+					"since this will become no longer publicly accessible after release v3.40.",
+					"GET /v1/vpn/status")
+				logger.EXPECT().Debugf("access to route %s authorized for role %s",
+					"GET /v1/vpn/status", "public")
+				return logger
+			},
+			requestMethod: http.MethodGet,
+			requestPath:   "/v1/vpn/status",
+			statusCode:    http.StatusOK,
+		},
+		"authorized_none": {
+			settings: Settings{
+				Roles: []Role{
+					{Name: "role1", Auth: AuthNone, Routes: []string{"GET /a"}},
+				},
+			},
+			makeLogger: func(ctrl *gomock.Controller) *MockDebugLogger {
+				logger := NewMockDebugLogger(ctrl)
+				logger.EXPECT().Debugf("access to route %s authorized for role %s",
+					"GET /a", "role1")
+				return logger
+			},
+			requestMethod: http.MethodGet,
+			requestPath:   "/a",
+			statusCode:    http.StatusOK,
+		},
+	}
+
+	for name, testCase := range testCases {
+		testCase := testCase
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			ctrl := gomock.NewController(t)
+
+			var debugLogger DebugLogger
+			if testCase.makeLogger != nil {
+				debugLogger = testCase.makeLogger(ctrl)
+			}
+			middleware, err := New(testCase.settings, debugLogger)
+			require.NoError(t, err)
+
+			childHandler := http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+				w.WriteHeader(http.StatusOK)
+			})
+			handler := middleware(childHandler)
+
+			server := httptest.NewServer(handler)
+			t.Cleanup(server.Close)
+
+			client := server.Client()
+
+			requestURL, err := url.JoinPath(server.URL, testCase.requestPath)
+			require.NoError(t, err)
+			request, err := http.NewRequestWithContext(context.Background(),
+				testCase.requestMethod, requestURL, nil)
+			require.NoError(t, err)
+
+			response, err := client.Do(request)
+			require.NoError(t, err)
+			t.Cleanup(func() {
+				err = response.Body.Close()
+				assert.NoError(t, err)
+			})
+
+			assert.Equal(t, testCase.statusCode, response.StatusCode)
+			body, err := io.ReadAll(response.Body)
+			require.NoError(t, err)
+			assert.Equal(t, testCase.responseBody, string(body))
+		})
+	}
+}

internal/server/middlewares/auth/mocks_generate_test.go

@@ -0,0 +1,3 @@
+package auth
+
+//go:generate mockgen -destination=mocks_test.go -package=$GOPACKAGE . DebugLogger

internal/server/middlewares/auth/mocks_test.go

@@ -0,0 +1,68 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: github.com/qdm12/gluetun/internal/server/middlewares/auth (interfaces: DebugLogger)
+
+// Package auth is a generated GoMock package.
+package auth
+
+import (
+	reflect "reflect"
+
+	gomock "github.com/golang/mock/gomock"
+)
+
+// MockDebugLogger is a mock of DebugLogger interface.
+type MockDebugLogger struct {
+	ctrl     *gomock.Controller
+	recorder *MockDebugLoggerMockRecorder
+}
+
+// MockDebugLoggerMockRecorder is the mock recorder for MockDebugLogger.
+type MockDebugLoggerMockRecorder struct {
+	mock *MockDebugLogger
+}
+
+// NewMockDebugLogger creates a new mock instance.
+func NewMockDebugLogger(ctrl *gomock.Controller) *MockDebugLogger {
+	mock := &MockDebugLogger{ctrl: ctrl}
+	mock.recorder = &MockDebugLoggerMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockDebugLogger) EXPECT() *MockDebugLoggerMockRecorder {
+	return m.recorder
+}
+
+// Debugf mocks base method.
+func (m *MockDebugLogger) Debugf(arg0 string, arg1 ...interface{}) {
+	m.ctrl.T.Helper()
+	varargs := []interface{}{arg0}
+	for _, a := range arg1 {
+		varargs = append(varargs, a)
+	}
+	m.ctrl.Call(m, "Debugf", varargs...)
+}
+
+// Debugf indicates an expected call of Debugf.
+func (mr *MockDebugLoggerMockRecorder) Debugf(arg0 interface{}, arg1 ...interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	varargs := append([]interface{}{arg0}, arg1...)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Debugf", reflect.TypeOf((*MockDebugLogger)(nil).Debugf), varargs...)
+}
+
+// Warnf mocks base method.
+func (m *MockDebugLogger) Warnf(arg0 string, arg1 ...interface{}) {
+	m.ctrl.T.Helper()
+	varargs := []interface{}{arg0}
+	for _, a := range arg1 {
+		varargs = append(varargs, a)
+	}
+	m.ctrl.Call(m, "Warnf", varargs...)
+}
+
+// Warnf indicates an expected call of Warnf.
+func (mr *MockDebugLoggerMockRecorder) Warnf(arg0 interface{}, arg1 ...interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	varargs := append([]interface{}{arg0}, arg1...)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Warnf", reflect.TypeOf((*MockDebugLogger)(nil).Warnf), varargs...)
+}

internal/server/middlewares/auth/none.go

@@ -0,0 +1,20 @@
+package auth
+
+import "net/http"
+
+type noneMethod struct{}
+
+func newNoneMethod() *noneMethod {
+	return &noneMethod{}
+}
+
+// equal returns true if another auth checker is equal.
+// This is used to deduplicate checkers for a particular route.
+func (n *noneMethod) equal(other authorizationChecker) bool {
+	_, ok := other.(*noneMethod)
+	return ok
+}
+
+func (n *noneMethod) isAuthorized(_ http.Header, _ *http.Request) bool {
+	return true
+}

internal/server/middlewares/auth/settings.go

@@ -0,0 +1,131 @@
+package auth
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/qdm12/gosettings"
+	"github.com/qdm12/gosettings/validate"
+)
+
+type Settings struct {
+	// Roles is a list of roles with their associated authentication
+	// and routes.
+	Roles []Role
+}
+
+func (s *Settings) SetDefaults() {
+	s.Roles = gosettings.DefaultSlice(s.Roles, []Role{{ // TODO v3.41.0 leave empty
+		Name: "public",
+		Auth: "none",
+		Routes: []string{
+			http.MethodGet + " /openvpn/actions/restart",
+			http.MethodGet + " /unbound/actions/restart",
+			http.MethodGet + " /updater/restart",
+			http.MethodGet + " /v1/version",
+			http.MethodGet + " /v1/vpn/status",
+			http.MethodPut + " /v1/vpn/status",
+			http.MethodGet + " /v1/openvpn/status",
+			http.MethodPut + " /v1/openvpn/status",
+			http.MethodGet + " /v1/openvpn/portforwarded",
+			http.MethodGet + " /v1/dns/status",
+			http.MethodPut + " /v1/dns/status",
+			http.MethodGet + " /v1/updater/status",
+			http.MethodPut + " /v1/updater/status",
+			http.MethodGet + " /v1/publicip/ip",
+		},
+	}})
+}
+
+func (s Settings) Validate() (err error) {
+	for i, role := range s.Roles {
+		err = role.validate()
+		if err != nil {
+			return fmt.Errorf("role %s (%d of %d): %w",
+				role.Name, i+1, len(s.Roles), err)
+		}
+	}
+
+	return nil
+}
+
+const (
+	AuthNone   = "none"
+	AuthAPIKey = "apikey"
+	AuthBasic  = "basic"
+)
+
+// Role contains the role name, authentication method name and
+// routes that the role can access.
+type Role struct {
+	// Name is the role name and is only used for documentation
+	// and in the authentication middleware debug logs.
+	Name string
+	// Auth is the authentication method to use, which can be 'none' or 'apikey'.
+	Auth string
+	// APIKey is the API key to use when using the 'apikey' authentication.
+	APIKey string
+	// Username for HTTP Basic authentication method.
+	Username string
+	// Password for HTTP Basic authentication method.
+	Password string
+	// Routes is a list of routes that the role can access in the format
+	// "HTTP_METHOD PATH", for example "GET /v1/vpn/status"
+	Routes []string
+}
+
+var (
+	ErrMethodNotSupported = errors.New("authentication method not supported")
+	ErrAPIKeyEmpty        = errors.New("api key is empty")
+	ErrBasicUsernameEmpty = errors.New("username is empty")
+	ErrBasicPasswordEmpty = errors.New("password is empty")
+	ErrRouteNotSupported  = errors.New("route not supported by the control server")
+)
+
+func (r Role) validate() (err error) {
+	err = validate.IsOneOf(r.Auth, AuthNone, AuthAPIKey, AuthBasic)
+	if err != nil {
+		return fmt.Errorf("%w: %s", ErrMethodNotSupported, r.Auth)
+	}
+
+	switch {
+	case r.Auth == AuthAPIKey && r.APIKey == "":
+		return fmt.Errorf("for role %s: %w", r.Name, ErrAPIKeyEmpty)
+	case r.Auth == AuthBasic && r.Username == "":
+		return fmt.Errorf("for role %s: %w", r.Name, ErrBasicUsernameEmpty)
+	case r.Auth == AuthBasic && r.Password == "":
+		return fmt.Errorf("for role %s: %w", r.Name, ErrBasicPasswordEmpty)
+	}
+
+	for i, route := range r.Routes {
+		_, ok := validRoutes[route]
+		if !ok {
+			return fmt.Errorf("route %d of %d: %w: %s",
+				i+1, len(r.Routes), ErrRouteNotSupported, route)
+		}
+	}
+
+	return nil
+}
+
+// WARNING: do not mutate programmatically.
+var validRoutes = map[string]struct{}{ //nolint:gochecknoglobals
+	http.MethodGet + " /openvpn/actions/restart":  {},
+	http.MethodGet + " /unbound/actions/restart":  {},
+	http.MethodGet + " /updater/restart":          {},
+	http.MethodGet + " /v1/version":               {},
+	http.MethodGet + " /v1/vpn/status":            {},
+	http.MethodPut + " /v1/vpn/status":            {},
+	http.MethodGet + " /v1/vpn/settings":          {},
+	http.MethodPut + " /v1/vpn/settings":          {},
+	http.MethodGet + " /v1/openvpn/status":        {},
+	http.MethodPut + " /v1/openvpn/status":        {},
+	http.MethodGet + " /v1/openvpn/portforwarded": {},
+	http.MethodGet + " /v1/openvpn/settings":      {},
+	http.MethodGet + " /v1/dns/status":            {},
+	http.MethodPut + " /v1/dns/status":            {},
+	http.MethodGet + " /v1/updater/status":        {},
+	http.MethodPut + " /v1/updater/status":        {},
+	http.MethodGet + " /v1/publicip/ip":           {},
+}

internal/server/middlewares/log/interfaces.go

@@ -0,0 +1,5 @@
+package log
+
+type Logger interface {
+	Info(message string)
+}

internal/server/middlewares/log/middleware.go

@@ -1,4 +1,4 @@
-package server
+package log
 
 import (
 	"net/http"
@@ -7,18 +7,21 @@ import (
 	"time"
 )
 
-func withLogMiddleware(childHandler http.Handler, logger infoer, enabled bool) *logMiddleware {
+func New(logger Logger, enabled bool) (
-	return &logMiddleware{
+	middleware func(http.Handler) http.Handler) {
-		childHandler: childHandler,
+	return func(handler http.Handler) http.Handler {
-		logger:       logger,
+		return &logMiddleware{
-		timeNow:      time.Now,
+			childHandler: handler,
-		enabled:      enabled,
+			logger:       logger,
+			timeNow:      time.Now,
+			enabled:      enabled,
+		}
 	}
 }
 
 type logMiddleware struct {
 	childHandler http.Handler
-	logger       infoer
+	logger       Logger
 	timeNow      func() time.Time
 	enabled      bool
 	enabledMu    sync.RWMutex
@@ -39,7 +42,7 @@ func (m *logMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		r.RemoteAddr + " in " + duration.String())
 }
 
-func (m *logMiddleware) setEnabled(enabled bool) {
+func (m *logMiddleware) SetEnabled(enabled bool) {
 	m.enabledMu.Lock()
 	defer m.enabledMu.Unlock()
 	m.enabled = enabled

internal/server/server.go

@@ -6,17 +6,31 @@ import (
 
 	"github.com/qdm12/gluetun/internal/httpserver"
 	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/server/middlewares/auth"
 )
 
 func New(ctx context.Context, address string, logEnabled bool, logger Logger,
-	buildInfo models.BuildInformation, openvpnLooper VPNLooper,
+	authConfigPath string, buildInfo models.BuildInformation, openvpnLooper VPNLooper,
 	pfGetter PortForwardedGetter, unboundLooper DNSLoop,
 	updaterLooper UpdaterLooper, publicIPLooper PublicIPLoop, storage Storage,
 	ipv6Supported bool) (
 	server *httpserver.Server, err error) {
-	handler := newHandler(ctx, logger, logEnabled, buildInfo,
+	authSettings, err := auth.Read(authConfigPath)
+	if err != nil {
+		return nil, fmt.Errorf("reading auth settings: %w", err)
+	}
+	authSettings.SetDefaults()
+	err = authSettings.Validate()
+	if err != nil {
+		return nil, fmt.Errorf("validating auth settings: %w", err)
+	}
+
+	handler, err := newHandler(ctx, logger, logEnabled, authSettings, buildInfo,
 		openvpnLooper, pfGetter, unboundLooper, updaterLooper, publicIPLooper,
 		storage, ipv6Supported)
+	if err != nil {
+		return nil, fmt.Errorf("creating handler: %w", err)
+	}
 
 	httpServerSettings := httpserver.Settings{
 		Address: address,

internal/storage/formatting.go

@@ -128,6 +128,31 @@ func noServerFoundError(selection settings.ServerSelection) (err error) {
 		messageParts = append(messageParts, "premium tier only")
 	}
 
+	if *selection.StreamOnly {
+		messageParts = append(messageParts, "stream only")
+	}
+
+	if *selection.MultiHopOnly {
+		messageParts = append(messageParts, "multihop only")
+	}
+
+	if *selection.PortForwardOnly {
+		messageParts = append(messageParts, "port forwarding only")
+	}
+
+	if *selection.SecureCoreOnly {
+		messageParts = append(messageParts, "secure core only")
+	}
+
+	if *selection.TorOnly {
+		messageParts = append(messageParts, "tor only")
+	}
+
+	if selection.TargetIP.IsValid() {
+		messageParts = append(messageParts,
+			"target ip address "+selection.TargetIP.String())
+	}
+
 	message := "for " + strings.Join(messageParts, "; ")
 
 	return fmt.Errorf("%w: %s", ErrNoServerFound, message)