feat(dns): restrict plain DNS output traffic

.github/workflows/ci.yml

@@ -59,16 +59,19 @@ jobs:
       - name: Run tests in test container
         run: |
           touch coverage.txt
-          docker run --rm --device /dev/net/tun \
+          docker run --rm --cap-add=NET_ADMIN --device /dev/net/tun \
           -v "$(pwd)/coverage.txt:/tmp/gobuild/coverage.txt" \
           test-container
 
+      - name: Verify dev cross platform compatibility
+        run: docker build --target xcompile .
+
       - name: Build final image
         run: docker build -t final-image .
 
   verify-private:
     if: |
-      github.repository == 'passteque/gluetun' &&
+      github.repository == 'qdm12/gluetun' &&
       (
         github.event_name == 'push' ||
         github.event_name == 'release' ||
@@ -115,7 +118,7 @@ jobs:
 
   publish:
     if: |
-      github.repository == 'passteque/gluetun' &&
+      github.repository == 'qdm12/gluetun' &&
       (
         github.event_name == 'push' ||
         github.event_name == 'release' ||
@@ -127,7 +130,6 @@ jobs:
       contents: read
       packages: write
     runs-on: ubuntu-latest
-    environment: secrets
     steps:
       - uses: actions/checkout@v6
 
@@ -162,15 +164,11 @@ jobs:
         with:
           registry: ghcr.io
           username: qdm12
-          password: ${{ secrets.GHCR_PAT }}
+          password: ${{ github.token }}
 
       - name: Short commit
         id: shortcommit
-        run: |
-          # Use the PR head SHA if it exists, otherwise fallback to GITHUB_SHA
-          FULL_SHA="${{ github.event.pull_request.head.sha || github.sha }}"
-          SHORT_SHA=
-          echo "value=$(echo $FULL_SHA | cut -c1-7)" >> $GITHUB_OUTPUT
+        run: echo "::set-output name=value::$(git rev-parse --short HEAD)"
 
       - name: Build and push final image
         uses: docker/build-push-action@v6

.github/workflows/markdown.yml

@@ -38,7 +38,7 @@ jobs:
           config-file: .github/workflows/configs/mlc-config.json
 
       - uses: peter-evans/dockerhub-description@v4
-        if: github.repository == 'passteque/gluetun' && github.event_name == 'push'
+        if: github.repository == 'qdm12/gluetun' && github.event_name == 'push'
         with:
           username: qmcgaw
           password: ${{ secrets.DOCKERHUB_PASSWORD }}

Dockerfile

@@ -46,6 +46,10 @@ RUN git init && \
     git diff --exit-code && \
     rm -rf .git/
 
+FROM --platform=${BUILDPLATFORM} base AS xcompile
+RUN GOOS=darwin go build -o /dev/null ./...
+RUN GOOS=windows go build -o /dev/null ./...
+
 FROM --platform=${BUILDPLATFORM} base AS build
 ARG TARGETPLATFORM
 ARG VERSION=unknown

cmd/gluetun/main.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/fs"
 	"net/http"
+	"net/netip"
 	"os"
 	"os/exec"
 	"os/signal"
@@ -15,8 +16,6 @@ import (
 	_ "time/tzdata"
 
 	_ "github.com/breml/rootcerts"
-	"github.com/qdm12/dns/v2/pkg/doh"
-	dnsprovider "github.com/qdm12/dns/v2/pkg/provider"
 	"github.com/qdm12/gluetun/internal/alpine"
 	"github.com/qdm12/gluetun/internal/cli"
 	"github.com/qdm12/gluetun/internal/command"
@@ -41,6 +40,7 @@ import (
 	"github.com/qdm12/gluetun/internal/server"
 	"github.com/qdm12/gluetun/internal/shadowsocks"
 	"github.com/qdm12/gluetun/internal/storage"
+	"github.com/qdm12/gluetun/internal/tun"
 	updater "github.com/qdm12/gluetun/internal/updater/loop"
 	"github.com/qdm12/gluetun/internal/updater/resolver"
 	"github.com/qdm12/gluetun/internal/updater/unzip"
@@ -77,6 +77,7 @@ func main() {
 	logger := log.New(log.SetLevel(log.LevelInfo))
 
 	args := os.Args
+	tun := tun.New()
 	netLinkDebugLogger := logger.New(log.SetComponent("netlink"))
 	netLinker := netlink.New(netLinkDebugLogger)
 	cli := cli.New()
@@ -96,7 +97,7 @@ func main() {
 
 	errorCh := make(chan error)
 	go func() {
-		errorCh <- _main(ctx, buildInfo, args, logger, reader, netLinker, cmder, cli)
+		errorCh <- _main(ctx, buildInfo, args, logger, reader, tun, netLinker, cmder, cli)
 	}()
 
 	// Wait for OS signal or run error
@@ -143,7 +144,7 @@ var errCommandUnknown = errors.New("command is unknown")
 //nolint:gocognit,gocyclo,maintidx
 func _main(ctx context.Context, buildInfo models.BuildInformation,
 	args []string, logger log.LoggerInterface, reader *reader.Reader,
-	netLinker netLinker, cmder RunStarter,
+	tun Tun, netLinker netLinker, cmder RunStarter,
 	cli clier,
 ) error {
 	if len(args) > 1 { // cli operation
@@ -263,7 +264,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	puid, pgid := int(*allSettings.System.PUID), int(*allSettings.System.PGID)
 
-	const clientTimeout = 35 * time.Second
+	const clientTimeout = 15 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
 	// Create configurators
 	alpineConf := alpine.New()
@@ -335,6 +336,19 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		return fmt.Errorf("adding local rules: %w", err)
 	}
 
+	const tunDevice = "/dev/net/tun"
+	err = tun.Check(tunDevice)
+	if err != nil {
+		if !errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("checking TUN device: %w (see the Wiki errors/tun page)", err)
+		}
+		logger.Info(err.Error() + "; creating it...")
+		err = tun.Create(tunDevice)
+		if err != nil {
+			return fmt.Errorf("creating tun device: %w", err)
+		}
+	}
+
 	for _, port := range allSettings.Firewall.InputPorts {
 		for _, defaultRoute := range defaultRoutes {
 			err = firewallConf.SetAllowedPort(ctx, port, defaultRoute.NetInterface)
@@ -380,7 +394,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	}
 
 	dnsLogger := logger.New(log.SetComponent("dns"))
-	dnsLooper, err := dns.NewLoop(allSettings.DNS, httpClient,
+	dnsLooper, err := dns.NewLoop(allSettings.DNS, httpClient, firewallConf,
 		dnsLogger)
 	if err != nil {
 		return fmt.Errorf("creating DNS loop: %w", err)
@@ -414,18 +428,10 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	go healthcheckServer.Run(healthServerCtx, healthServerDone)
 	healthChecker := healthcheck.NewChecker(healthLogger)
 
-	// Note: we use a separate DoH dialer for the VPN servers data updater, separate from the
-	// main DNS local server to make sure no request is blocked by filters.
-	dohDialer, err := doh.New(doh.Settings{
-		UpstreamResolvers: []dnsprovider.Provider{dnsprovider.Cloudflare(), dnsprovider.Google()},
-	})
-	if err != nil {
-		return fmt.Errorf("creating updater DoH dialer: %w", err)
-	}
 	updaterLogger := logger.New(log.SetComponent("updater"))
 
 	unzipper := unzip.New(httpClient)
-	parallelResolver := resolver.NewParallelResolver(dohDialer)
+	parallelResolver := resolver.NewParallelResolver(allSettings.Updater.DNSAddress)
 	openvpnFileExtractor := extract.New()
 	providers := provider.NewProviders(storage, time.Now, updaterLogger,
 		httpClient, unzipper, parallelResolver, publicIPLooper.Fetcher(),
@@ -548,26 +554,26 @@ type netLinker interface {
 	Router
 	Ruler
 	Linker
-	IsWireguardSupported() bool
+	IsWireguardSupported() (ok bool, err error)
 	IsIPv6Supported() (ok bool, err error)
 	PatchLoggerLevel(level log.Level)
 }
 
 type Addresser interface {
-	AddrList(link netlink.Link, family int) (
-		addresses []netlink.Addr, err error)
-	AddrReplace(link netlink.Link, addr netlink.Addr) error
+	AddrList(linkIndex uint32, family uint8) (
+		addresses []netip.Prefix, err error)
+	AddrReplace(linkIndex uint32, addr netip.Prefix) error
 }
 
 type Router interface {
-	RouteList(family int) (routes []netlink.Route, err error)
+	RouteList(family uint8) (routes []netlink.Route, err error)
 	RouteAdd(route netlink.Route) error
 	RouteDel(route netlink.Route) error
 	RouteReplace(route netlink.Route) error
 }
 
 type Ruler interface {
-	RuleList(family int) (rules []netlink.Rule, err error)
+	RuleList(family uint8) (rules []netlink.Rule, err error)
 	RuleAdd(rule netlink.Rule) error
 	RuleDel(rule netlink.Rule) error
 }
@@ -575,11 +581,12 @@ type Ruler interface {
 type Linker interface {
 	LinkList() (links []netlink.Link, err error)
 	LinkByName(name string) (link netlink.Link, err error)
-	LinkByIndex(index int) (link netlink.Link, err error)
-	LinkAdd(link netlink.Link) (linkIndex int, err error)
-	LinkDel(link netlink.Link) (err error)
-	LinkSetUp(link netlink.Link) (linkIndex int, err error)
-	LinkSetDown(link netlink.Link) (err error)
+	LinkByIndex(index uint32) (link netlink.Link, err error)
+	LinkAdd(link netlink.Link) (linkIndex uint32, err error)
+	LinkDel(linkIndex uint32) (err error)
+	LinkSetUp(linkIndex uint32) (err error)
+	LinkSetDown(linkIndex uint32) (err error)
+	LinkSetMTU(linkIndex, mtu uint32) error
 }
 
 type clier interface {
@@ -591,6 +598,11 @@ type clier interface {
 	GenKey(args []string) error
 }
 
+type Tun interface {
+	Check(tunDevice string) error
+	Create(tunDevice string) error
+}
+
 type RunStarter interface {
 	Run(cmd *exec.Cmd) (output string, err error)
 	Start(cmd *exec.Cmd) (stdoutLines, stderrLines <-chan string,

go.mod

@@ -7,10 +7,12 @@ require (
 	github.com/breml/rootcerts v0.3.3
 	github.com/fatih/color v1.18.0
 	github.com/golang/mock v1.6.0
+	github.com/jsimonetti/rtnetlink v1.4.2
 	github.com/klauspost/compress v1.18.1
 	github.com/klauspost/pgzip v1.2.6
+	github.com/mdlayher/genetlink v1.3.2
 	github.com/pelletier/go-toml/v2 v2.2.4
-	github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260421173011-9de8e7fdbe3a
+	github.com/qdm12/dns/v2 v2.0.0-rc10
 	github.com/qdm12/gosettings v0.4.4
 	github.com/qdm12/goshutdown v0.3.0
 	github.com/qdm12/gosplash v0.2.0
@@ -19,12 +21,11 @@ require (
 	github.com/qdm12/ss-server v0.6.0
 	github.com/stretchr/testify v1.11.1
 	github.com/ulikunitz/xz v0.5.15
-	github.com/vishvananda/netlink v1.3.1
 	github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a
 	golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c
-	golang.org/x/net v0.47.0
-	golang.org/x/sys v0.38.0
-	golang.org/x/text v0.31.0
+	golang.org/x/net v0.49.0
+	golang.org/x/sys v0.40.0
+	golang.org/x/text v0.33.0
 	golang.zx2c4.com/wireguard v0.0.0-20231211153847-12269c276173
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230429144221-925a1e7659e6
 	gopkg.in/ini.v1 v1.67.0
@@ -38,13 +39,12 @@ require (
 	github.com/cloudflare/circl v1.6.1 // indirect
 	github.com/cronokirby/saferith v0.33.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/google/go-cmp v0.6.0 // indirect
+	github.com/google/go-cmp v0.7.0 // indirect
 	github.com/josharian/native v1.1.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mdlayher/genetlink v1.3.2 // indirect
 	github.com/mdlayher/netlink v1.7.2 // indirect
-	github.com/mdlayher/socket v0.4.1 // indirect
+	github.com/mdlayher/socket v0.5.1 // indirect
 	github.com/miekg/dns v1.1.62 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
@@ -55,12 +55,11 @@ require (
 	github.com/prometheus/procfs v0.15.1 // indirect
 	github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978 // indirect
 	github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 // indirect
-	github.com/vishvananda/netns v0.0.5 // indirect
-	golang.org/x/crypto v0.45.0 // indirect
-	golang.org/x/mod v0.29.0 // indirect
-	golang.org/x/sync v0.18.0 // indirect
+	golang.org/x/crypto v0.47.0 // indirect
+	golang.org/x/mod v0.31.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
 	golang.org/x/time v0.3.0 // indirect
-	golang.org/x/tools v0.38.0 // indirect
+	golang.org/x/tools v0.40.0 // indirect
 	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
 	google.golang.org/protobuf v1.35.1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -13,6 +13,8 @@ github.com/breml/rootcerts v0.3.3/go.mod h1:S/PKh+4d1HUn4HQovEB8hPJZO6pUZYrIhmXB
 github.com/bwesterb/go-ristretto v1.2.0/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7NFEuV9ekS419A0=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/cilium/ebpf v0.12.3 h1:8ht6F9MquybnY97at+VDZb3eQQr8ev79RueWeVaEcG4=
+github.com/cilium/ebpf v0.12.3/go.mod h1:TctK1ivibvI3znr66ljgi4hqOT8EYQjz1KWBfb1UVgM=
 github.com/cloudflare/circl v1.1.0/go.mod h1:prBCrKB9DV4poKZY1l9zBXg2QJY7mvgRvtMxxK7fi4I=
 github.com/cloudflare/circl v1.6.1 h1:zqIqSPIndyBh1bjLVVDHMPpVKqp8Su/V+6MeDzzQBQ0=
 github.com/cloudflare/circl v1.6.1/go.mod h1:uddAzsPgqdMAYatqJ0lsjX1oECcQLIlRpzZh3pJrofs=
@@ -26,10 +28,12 @@ github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
 github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
 github.com/google/btree v1.0.1 h1:gK4Kx5IaGY9CD5sPJ36FHiBJ6ZXl0kilRiiCj+jdYp4=
 github.com/google/btree v1.0.1/go.mod h1:xXMiIv4Fb/0kKde4SpL7qlzvu5cMJDRkFDxJfI9uaxA=
-github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
-github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
+github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/josharian/native v1.1.0 h1:uuaP0hAbW7Y4l0ZRQ6C9zfb7Mg1mbFKry/xzDAfmtLA=
 github.com/josharian/native v1.1.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
+github.com/jsimonetti/rtnetlink v1.4.2 h1:Df9w9TZ3npHTyDn0Ev9e1uzmN2odmXd0QX+J5GTEn90=
+github.com/jsimonetti/rtnetlink v1.4.2/go.mod h1:92s6LJdE+1iOrw+F2/RO7LYI2Qd8pPpFNNUYW06gcoM=
 github.com/klauspost/compress v1.18.1 h1:bcSGx7UbpBqMChDtsF28Lw6v/G94LPrrbMbdC3JH2co=
 github.com/klauspost/compress v1.18.1/go.mod h1:ZQFFVG+MdnR0P+l6wpXgIL4NTtwiKIdBnrBd8Nrxr+0=
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
@@ -47,8 +51,8 @@ github.com/mdlayher/genetlink v1.3.2 h1:KdrNKe+CTu+IbZnm/GVUMXSqBBLqcGpRDa0xkQy5
 github.com/mdlayher/genetlink v1.3.2/go.mod h1:tcC3pkCrPUGIKKsCsp0B3AdaaKuHtaxoJRz3cc+528o=
 github.com/mdlayher/netlink v1.7.2 h1:/UtM3ofJap7Vl4QWCPDGXY8d3GIY2UGSDbK+QWmY8/g=
 github.com/mdlayher/netlink v1.7.2/go.mod h1:xraEF7uJbxLhc5fpHL4cPe221LI2bdttWlU+ZGLfQSw=
-github.com/mdlayher/socket v0.4.1 h1:eM9y2/jlbs1M615oshPQOHZzj6R6wMT7bX5NPiQvn2U=
-github.com/mdlayher/socket v0.4.1/go.mod h1:cAqeGjoufqdxWkD7DkpyS+wcefOtmu5OQ8KuoJGIReA=
+github.com/mdlayher/socket v0.5.1 h1:VZaqt6RkGkt2OE9l3GcC6nZkqD3xKeQLyfleW/uBcos=
+github.com/mdlayher/socket v0.5.1/go.mod h1:TjPLHI1UgwEv5J1B5q0zTZq12A/6H7nKmtTanQE37IQ=
 github.com/miekg/dns v1.1.62 h1:cN8OuEF1/x5Rq6Np+h1epln8OiyPWV+lROx9LxcGgIQ=
 github.com/miekg/dns v1.1.62/go.mod h1:mvDlcItzm+br7MToIKqkglaGhlFMHJ9DTNNWONWXbNQ=
 github.com/mikioh/ipaddr v0.0.0-20190404000644-d465c8ab6721 h1:RlZweED6sbSArvlE924+mUcZuXKLBHA35U7LN621Bws=
@@ -69,8 +73,8 @@ github.com/prometheus/common v0.60.1 h1:FUas6GcOw66yB/73KC+BOZoFJmbo/1pojoILArPA
 github.com/prometheus/common v0.60.1/go.mod h1:h0LYf1R1deLSKtD4Vdg8gy4RuOvENW2J/h19V5NADQw=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
-github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260421173011-9de8e7fdbe3a h1:TE157yPQmAbVruH0MWCQzs0vTT/6t96DkoWUXd6PVuc=
-github.com/qdm12/dns/v2 v2.0.0-rc9.0.20260421173011-9de8e7fdbe3a/go.mod h1:98foWgXJZ+g8gJIuO+fdO+oWpFei5WShMFTeN4Im2lE=
+github.com/qdm12/dns/v2 v2.0.0-rc10 h1:IyeNEYXfhBsaE1dwxx5eAqdAz1HS98dT+8c7xoKODa0=
+github.com/qdm12/dns/v2 v2.0.0-rc10/go.mod h1:98foWgXJZ+g8gJIuO+fdO+oWpFei5WShMFTeN4Im2lE=
 github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978 h1:TRGpCU1l0lNwtogEUSs5U+RFceYxkAJUmrGabno7J5c=
 github.com/qdm12/goservices v0.1.1-0.20251104135713-6bee97bd4978/go.mod h1:D1Po4CRQLYjccnAR2JsVlN1sBMgQrcNLONbvyuzcdTg=
 github.com/qdm12/gosettings v0.4.4 h1:SM6tOZDf6k8qbjWU8KWyBF4mWIixfsKCfh9DGRLHlj4=
@@ -93,10 +97,6 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/ulikunitz/xz v0.5.15 h1:9DNdB5s+SgV3bQ2ApL10xRc35ck0DuIX/isZvIk+ubY=
 github.com/ulikunitz/xz v0.5.15/go.mod h1:nbz6k7qbPmH4IRqmfOplQw/tblSgqTqBwxkY0oWt/14=
-github.com/vishvananda/netlink v1.3.1 h1:3AEMt62VKqz90r0tmNhog0r/PpWKmrEShJU0wJW6bV0=
-github.com/vishvananda/netlink v1.3.1/go.mod h1:ARtKouGSTGchR8aMwmkzC0qiNPrrWO5JS/XMVl45+b4=
-github.com/vishvananda/netns v0.0.5 h1:DfiHV+j8bA32MFM7bfEunvT8IAqQ/NzSJHtcmW5zdEY=
-github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZlaprSwhNNJM=
 github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a h1:fZHgsYlfvtyqToslyjUt3VOPF4J7aK/3MPcK7xp3PDk=
 github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a/go.mod h1:ul22v+Nro/R083muKhosV54bj5niojjWZvU8xrevuH4=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
@@ -106,15 +106,15 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200302210943-78000ba7a073/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
-golang.org/x/crypto v0.45.0 h1:jMBrvKuj23MTlT0bQEOBcAE0mjg8mK9RXFhRH6nyF3Q=
-golang.org/x/crypto v0.45.0/go.mod h1:XTGrrkGJve7CYK7J8PEww4aY7gM3qMCElcJQ8n8JdX4=
+golang.org/x/crypto v0.47.0 h1:V6e3FRj+n4dbpw86FJ8Fv7XVOql7TEwpHapKoMJ/GO8=
+golang.org/x/crypto v0.47.0/go.mod h1:ff3Y9VzzKbwSSEzWqJsJVBnWmRwRSHt/6Op5n9bQc4A=
 golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c h1:7dEasQXItcW1xKJ2+gg5VOiBnqWrJc+rq0DPKyvvdbY=
 golang.org/x/exp v0.0.0-20241009180824-f66d83c29e7c/go.mod h1:NQtJDoLvd6faHhE7m4T/1IY708gDefGGjR/iUW8yQQ8=
 golang.org/x/mod v0.4.2/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
-golang.org/x/mod v0.29.0 h1:HV8lRxZC4l2cr3Zq1LvtOsi/ThTgWnUk/y64QSs8GwA=
-golang.org/x/mod v0.29.0/go.mod h1:NyhrlYXJ2H4eJiRy/WDBO6HMqZQ6q9nk4JzS3NuCK+w=
+golang.org/x/mod v0.31.0 h1:HaW9xtz0+kOcWKwli0ZXy79Ix+UW/vOfmWI5QVd2tgI=
+golang.org/x/mod v0.31.0/go.mod h1:43JraMp9cGx1Rx3AqioxrbrhNsLl2l/iNAvuBkrezpg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
@@ -122,14 +122,14 @@ golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96b
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
 golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
-golang.org/x/net v0.47.0 h1:Mx+4dIFzqraBXUugkia1OOvlD6LemFo1ALMHjrXDOhY=
-golang.org/x/net v0.47.0/go.mod h1:/jNxtkgq5yWUGYkaZGqo27cfGZ1c5Nen03aYrrKpVRU=
+golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
+golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.18.0 h1:kr88TuHDroi+UVf+0hZnirlk8o8T+4MrK6mr60WkH/I=
-golang.org/x/sync v0.18.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
+golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
+golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -140,12 +140,10 @@ golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBc
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
-golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.40.0 h1:DBZZqJ2Rkml6QMQsZywtnjnnGvHza6BTfYFWY9kjEWQ=
+golang.org/x/sys v0.40.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/term v0.5.0/go.mod h1:jMB1sMXY+tzblOD4FWmEbocvup2/aLOaQEp7JmGp78k=
@@ -155,8 +153,8 @@ golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
-golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
-golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
+golang.org/x/text v0.33.0 h1:B3njUFyqtHDUI5jMn1YIr5B0IE2U0qck04r6d4KPAxE=
+golang.org/x/text v0.33.0/go.mod h1:LuMebE6+rBincTi9+xWTY8TztLzKHc/9C1uBCG27+q8=
 golang.org/x/time v0.3.0 h1:rg5rLMjNzMS1RkNLzCG38eapWhnYLFYXDXj2gOlr8j4=
 golang.org/x/time v0.3.0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
@@ -164,8 +162,8 @@ golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtn
 golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
-golang.org/x/tools v0.38.0 h1:Hx2Xv8hISq8Lm16jvBZ2VQf+RLmbd7wVUsALibYI/IQ=
-golang.org/x/tools v0.38.0/go.mod h1:yEsQ/d/YK8cjh0L6rZlY8tgtlKiBNTL14pGDJPJpYQs=
+golang.org/x/tools v0.40.0 h1:yLkxfA+Qnul4cs9QA3KnlFu0lVmd8JJfoq+E41uSutA=
+golang.org/x/tools v0.40.0/go.mod h1:Ik/tzLRlbscWpqqMRjyWYDisX8bG13FrdXp3o4Sr9lc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

internal/cli/update.go

@@ -10,8 +10,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/qdm12/dns/v2/pkg/doh"
-	dnsprovider "github.com/qdm12/dns/v2/pkg/provider"
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/constants/providers"
@@ -40,12 +38,12 @@ type UpdaterLogger interface {
 func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) error {
 	options := settings.Updater{}
 	var endUserMode, maintainerMode, updateAll bool
-	var dnsServer, csvProviders, ipToken, protonUsername, protonEmail, protonPassword string
+	var csvProviders, ipToken, protonUsername, protonEmail, protonPassword string
 	flagSet := flag.NewFlagSet("update", flag.ExitOnError)
 	flagSet.BoolVar(&endUserMode, "enduser", false, "Write results to /gluetun/servers.json (for end users)")
 	flagSet.BoolVar(&maintainerMode, "maintainer", false,
 		"Write results to ./internal/storage/servers.json to modify the program (for maintainers)")
-	flagSet.StringVar(&dnsServer, "dns", "", "no longer used, your DNS will use DoH with Cloudflare and Google")
+	flagSet.StringVar(&options.DNSAddress, "dns", "8.8.8.8", "DNS resolver address to use")
 	const defaultMinRatio = 0.8
 	flagSet.Float64Var(&options.MinRatio, "minratio", defaultMinRatio,
 		"Minimum ratio of servers to find for the update to succeed")
@@ -60,10 +58,6 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		return err
 	}
 
-	if dnsServer != "" {
-		logger.Warn("The -dns flag is no longer used, your DNS will use DoH with Cloudflare and Google")
-	}
-
 	if !endUserMode && !maintainerMode {
 		return fmt.Errorf("%w", ErrModeUnspecified)
 	}
@@ -103,21 +97,10 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		return fmt.Errorf("creating servers storage: %w", err)
 	}
 
-	dohSettings := doh.Settings{
-		UpstreamResolvers: []dnsprovider.Provider{
-			dnsprovider.Cloudflare(),
-			dnsprovider.Google(),
-		},
-	}
-	dnsDialer, err := doh.New(dohSettings)
-	if err != nil {
-		return fmt.Errorf("creating DoH dialer: %w", err)
-	}
-
 	const clientTimeout = 10 * time.Second
 	httpClient := &http.Client{Timeout: clientTimeout}
 	unzipper := unzip.New(httpClient)
-	parallelResolver := resolver.NewParallelResolver(dnsDialer)
+	parallelResolver := resolver.NewParallelResolver(options.DNSAddress)
 	nameTokenPairs := []api.NameToken{
 		{Name: string(api.IPInfo), Token: ipToken},
 		{Name: string(api.IP2Location)},

internal/command/start.go

@@ -9,9 +9,8 @@ import (
 )
 
 // Start launches a command and streams stdout and stderr to channels.
-// stdoutLines and stderrLines channels will be closed when there is no more
-// output to read, in order for the caller to catch all lines even after the
-// command has finished. The waitError channel returned will never be closed.
+// All the channels returned are ready only and won't be closed
+// if the command fails later.
 func (c *Cmder) Start(cmd *exec.Cmd) (
 	stdoutLines, stderrLines <-chan string,
 	waitError <-chan error, startErr error,
@@ -22,6 +21,7 @@ func (c *Cmder) Start(cmd *exec.Cmd) (
 func start(cmd execCmd) (stdoutLines, stderrLines <-chan string,
 	waitError <-chan error, startErr error,
 ) {
+	stop := make(chan struct{})
 	stdoutReady := make(chan struct{})
 	stdoutLinesCh := make(chan string)
 	stdoutDone := make(chan struct{})
@@ -33,47 +33,43 @@ func start(cmd execCmd) (stdoutLines, stderrLines <-chan string,
 	if err != nil {
 		return nil, nil, nil, err
 	}
-	go streamToChannel(stdoutReady, stdoutDone, stdout, stdoutLinesCh)
+	go streamToChannel(stdoutReady, stop, stdoutDone, stdout, stdoutLinesCh)
 
 	stderr, err := cmd.StderrPipe()
 	if err != nil {
 		_ = stdout.Close()
+		close(stop)
 		<-stdoutDone
-		close(stdoutLinesCh)
 		return nil, nil, nil, err
 	}
-	go streamToChannel(stderrReady, stderrDone, stderr, stderrLinesCh)
+	go streamToChannel(stderrReady, stop, stderrDone, stderr, stderrLinesCh)
 
 	err = cmd.Start()
 	if err != nil {
 		_ = stdout.Close()
-		<-stdoutDone
-		close(stdoutLinesCh)
 		_ = stderr.Close()
+		close(stop)
+		<-stdoutDone
 		<-stderrDone
-		close(stderrLinesCh)
 		return nil, nil, nil, err
 	}
 
 	waitErrorCh := make(chan error)
 	go func() {
 		err := cmd.Wait()
-		<-stdoutDone
-		close(stdoutLinesCh)
 		_ = stdout.Close()
-		<-stderrDone
-		close(stderrLinesCh)
 		_ = stderr.Close()
+		close(stop)
+		<-stdoutDone
+		<-stderrDone
 		waitErrorCh <- err
 	}()
 
-	<-stdoutReady
-	<-stderrReady
-
 	return stdoutLinesCh, stderrLinesCh, waitErrorCh, nil
 }
 
-func streamToChannel(ready chan<- struct{}, done chan<- struct{},
+func streamToChannel(ready chan<- struct{},
+	stop <-chan struct{}, done chan<- struct{},
 	stream io.Reader, lines chan<- string,
 ) {
 	defer close(done)
@@ -93,5 +89,12 @@ func streamToChannel(ready chan<- struct{}, done chan<- struct{},
 	if err == nil || errors.Is(err, os.ErrClosed) {
 		return
 	}
+
+	// ignore the error if it is stopped.
+	select {
+	case <-stop:
+		return
+	default:
 		lines <- "stream error: " + err.Error()
+	}
 }

internal/command/start_test.go

@@ -89,41 +89,21 @@ func Test_start(t *testing.T) {
 
 			require.NoError(t, err)
 
-			collectAndCheckChannels(t, stdoutLines, stderrLines, waitError,
-				testCase.stdout, testCase.stderr, testCase.waitErr)
-		})
-	}
-}
-
-func collectAndCheckChannels(t *testing.T, stdoutLines, stderrLines <-chan string,
-	waitError <-chan error, expectedStdout, expectedStderr []string, expectedWaitErr error,
-) {
-	t.Helper()
-
-	stdoutIndex := 0
-	stderrIndex := 0
+			var stdoutIndex, stderrIndex int
 
 			done := false
 			for !done {
 				select {
-		case line, ok := <-stdoutLines:
-			if !ok {
-				stdoutLines = nil
-				continue
-			}
-			assert.Equal(t, expectedStdout[stdoutIndex], line)
+				case line := <-stdoutLines:
+					assert.Equal(t, testCase.stdout[stdoutIndex], line)
 					stdoutIndex++
-		case line, ok := <-stderrLines:
-			if !ok {
-				stderrLines = nil
-				continue
-			}
-			assert.Equal(t, expectedStderr[stderrIndex], line)
+				case line := <-stderrLines:
+					assert.Equal(t, testCase.stderr[stderrIndex], line)
 					stderrIndex++
 				case err := <-waitError:
-			if expectedWaitErr != nil {
+					if testCase.waitErr != nil {
 						require.Error(t, err)
-				assert.Equal(t, expectedWaitErr.Error(), err.Error())
+						assert.Equal(t, testCase.waitErr.Error(), err.Error())
 					} else {
 						assert.NoError(t, err)
 					}
@@ -131,6 +111,8 @@ func collectAndCheckChannels(t *testing.T, stdoutLines, stderrLines <-chan strin
 				}
 			}
 
-	assert.Equal(t, len(expectedStdout), stdoutIndex)
-	assert.Equal(t, len(expectedStderr), stderrIndex)
+			assert.Equal(t, len(testCase.stdout), stdoutIndex)
+			assert.Equal(t, len(testCase.stderr), stderrIndex)
+		})
+	}
 }

internal/configuration/settings/openvpnselection.go

@@ -60,6 +60,7 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 		providers.Giganews,
 		providers.Ipvanish,
 		providers.Perfectprivacy,
+		providers.Privado,
 		providers.Vyprvpn,
 	) {
 		return fmt.Errorf("%w: for VPN service provider %s",
@@ -74,8 +75,8 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 			providers.Privatevpn, providers.Torguard:
 		// no custom port allowed
 		case providers.Expressvpn, providers.Fastestvpn,
-			providers.Giganews, providers.Ipvanish,
-			providers.Nordvpn, providers.Purevpn,
+			providers.Giganews, providers.Ipvanish, providers.Nordvpn,
+			providers.Privado, providers.Purevpn,
 			providers.Surfshark, providers.VPNSecure,
 			providers.VPNUnlimited, providers.Vyprvpn:
 			return fmt.Errorf("%w: for VPN service provider %s",
@@ -98,11 +99,8 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 			case providers.Perfectprivacy:
 				allowedTCP = []uint16{44, 443, 4433}
 				allowedUDP = []uint16{44, 443, 4433}
-			case providers.Privado:
-				allowedTCP = []uint16{443, 1194, 8080, 8443}
-				allowedUDP = []uint16{443, 1194, 8080, 8443}
 			case providers.PrivateInternetAccess:
-				allowedTCP = []uint16{80, 110, 443, 501, 502, 8443}
+				allowedTCP = []uint16{80, 110, 443}
 				allowedUDP = []uint16{53, 1194, 1197, 1198, 8080, 9201}
 			case providers.Protonvpn:
 				allowedTCP = []uint16{443, 5995, 8443}
@@ -132,6 +130,7 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 	// Validate EncPreset
 	if vpnProvider == providers.PrivateInternetAccess {
 		validEncryptionPresets := []string{
+			presets.None,
 			presets.Normal,
 			presets.Strong,
 		}

internal/configuration/settings/provider.go

@@ -48,6 +48,10 @@ func (p *Provider) validate(vpnType string, filterChoicesGetter FilterChoicesGet
 		return fmt.Errorf("%w for Wireguard: %w", ErrVPNProviderNameNotValid, err)
 	}
 
+	if p.Name == providers.Mullvad && vpnType == vpn.OpenVPN {
+		warner.Warn("https://mullvad.net/en/blog/removing-openvpn-15th-january-2026")
+	}
+
 	err = p.ServerSelection.validate(p.Name, filterChoicesGetter, warner)
 	if err != nil {
 		return fmt.Errorf("server selection: %w", err)

internal/configuration/settings/updater.go

@@ -21,6 +21,10 @@ type Updater struct {
 	// updater. It cannot be nil in the internal state.
 	// TODO change to value and add Enabled field.
 	Period *time.Duration
+	// DNSAddress is the DNS server address to use
+	// to resolve VPN server hostnames to IP addresses.
+	// It cannot be the empty string in the internal state.
+	DNSAddress string
 	// MinRatio is the minimum ratio of servers to
 	// find per provider, compared to the total current
 	// number of servers. It defaults to 0.8.
@@ -72,6 +76,7 @@ func (u Updater) Validate() (err error) {
 func (u *Updater) copy() (copied Updater) {
 	return Updater{
 		Period:         gosettings.CopyPointer(u.Period),
+		DNSAddress:     u.DNSAddress,
 		MinRatio:       u.MinRatio,
 		Providers:      gosettings.CopySlice(u.Providers),
 		ProtonEmail:    gosettings.CopyPointer(u.ProtonEmail),
@@ -84,6 +89,7 @@ func (u *Updater) copy() (copied Updater) {
 // settings.
 func (u *Updater) overrideWith(other Updater) {
 	u.Period = gosettings.OverrideWithPointer(u.Period, other.Period)
+	u.DNSAddress = gosettings.OverrideWithComparable(u.DNSAddress, other.DNSAddress)
 	u.MinRatio = gosettings.OverrideWithComparable(u.MinRatio, other.MinRatio)
 	u.Providers = gosettings.OverrideWithSlice(u.Providers, other.Providers)
 	u.ProtonEmail = gosettings.OverrideWithPointer(u.ProtonEmail, other.ProtonEmail)
@@ -92,6 +98,7 @@ func (u *Updater) overrideWith(other Updater) {
 
 func (u *Updater) SetDefaults(vpnProvider string) {
 	u.Period = gosettings.DefaultPointer(u.Period, 0)
+	u.DNSAddress = gosettings.DefaultComparable(u.DNSAddress, "1.1.1.1:53")
 
 	if u.MinRatio == 0 {
 		const defaultMinRatio = 0.8
@@ -118,6 +125,7 @@ func (u Updater) toLinesNode() (node *gotree.Node) {
 
 	node = gotree.New("Server data updater settings:")
 	node.Appendf("Update period: %s", *u.Period)
+	node.Appendf("DNS address: %s", u.DNSAddress)
 	node.Appendf("Minimum ratio: %.1f", u.MinRatio)
 	node.Appendf("Providers to update: %s", strings.Join(u.Providers, ", "))
 	if slices.Contains(u.Providers, providers.Protonvpn) {
@@ -134,6 +142,11 @@ func (u *Updater) read(r *reader.Reader) (err error) {
 		return err
 	}
 
+	u.DNSAddress, err = readUpdaterDNSAddress()
+	if err != nil {
+		return err
+	}
+
 	u.MinRatio, err = r.Float64("UPDATER_MIN_RATIO")
 	if err != nil {
 		return err
@@ -153,3 +166,12 @@ func (u *Updater) read(r *reader.Reader) (err error) {
 
 	return nil
 }
+
+func readUpdaterDNSAddress() (address string, err error) {
+	// TODO this is currently using Cloudflare in
+	// plaintext to not be blocked by DNS over TLS by default.
+	// If a plaintext address is set in the DNS settings, this one will be used.
+	// use custom future encrypted DNS written in Go without blocking
+	// as it's too much trouble to start another parallel unbound instance for now.
+	return "", nil
+}

internal/configuration/settings/wireguard.go

@@ -45,7 +45,8 @@ type Wireguard struct {
 	// It has been lowered to 1320 following quite a bit of
 	// investigation in the issue:
 	// https://github.com/qdm12/gluetun/issues/2533.
-	MTU uint16 `json:"mtu"`
+	// Note this should now be replaced with the PMTUD feature.
+	MTU uint32 `json:"mtu"`
 	// Implementation is the Wireguard implementation to use.
 	// It can be "auto", "userspace" or "kernelspace".
 	// It defaults to "auto" and cannot be the empty string
@@ -251,12 +252,10 @@ func (w *Wireguard) read(r *reader.Reader) (err error) {
 	// WARNING: do not initialize w.Addresses to an empty slice
 	// or the defaults for nordvpn will not work.
 	for _, addressString := range addressStrings {
-		addressString = strings.TrimSpace(addressString)
-		if addressString == "" {
-			continue
-		} else if !strings.ContainsRune(addressString, '/') {
+		if !strings.ContainsRune(addressString, '/') {
 			addressString += "/32"
 		}
+		addressString = strings.TrimSpace(addressString)
 		address, err := netip.ParsePrefix(addressString)
 		if err != nil {
 			return fmt.Errorf("parsing address: %w", err)
@@ -274,7 +273,7 @@ func (w *Wireguard) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	mtuPtr, err := r.Uint16Ptr("WIREGUARD_MTU")
+	mtuPtr, err := r.Uint32Ptr("WIREGUARD_MTU")
 	if err != nil {
 		return err
 	} else if mtuPtr != nil {

internal/configuration/sources/files/wireguard.go

@@ -3,10 +3,10 @@ package files
 import (
 	"errors"
 	"fmt"
-	"net"
 	"os"
 	"path/filepath"
 	"regexp"
+	"strings"
 
 	"gopkg.in/ini.v1"
 )
@@ -82,12 +82,12 @@ func parseWireguardPeerSection(peerSection *ini.Section) (
 	publicKey = getINIKeyFromSection(peerSection, "PublicKey")
 	endpoint := getINIKeyFromSection(peerSection, "Endpoint")
 	if endpoint != nil {
-		host, port, err := net.SplitHostPort(*endpoint)
-		if err == nil {
-			endpointIP = &host
-			endpointPort = &port
-		} else {
-			endpointIP = endpoint
+		parts := strings.Split(*endpoint, ":")
+		endpointIP = &parts[0]
+		const partsWithPort = 2
+		if len(parts) >= partsWithPort {
+			endpointPort = new(string)
+			*endpointPort = strings.Join(parts[1:], ":")
 		}
 	}
 

internal/configuration/sources/files/wireguard_test.go

@@ -179,12 +179,6 @@ Endpoint = 1.2.3.4:51820`,
 			endpointIP:   ptrTo("1.2.3.4"),
 			endpointPort: ptrTo("51820"),
 		},
-		"ipv6_endpoint": {
-			iniData: `[Peer]
-Endpoint = [2a02:bbbb:aaaa:8075::10]:51820`,
-			endpointIP:   ptrTo("2a02:bbbb:aaaa:8075::10"),
-			endpointPort: ptrTo("51820"),
-		},
 	}
 
 	for testName, testCase := range testCases {

internal/dns/interfaces.go

@@ -0,0 +1,17 @@
+package dns
+
+import (
+	"context"
+	"net/netip"
+)
+
+type Logger interface {
+	Debug(s string)
+	Info(s string)
+	Warn(s string)
+	Error(s string)
+}
+
+type Firewall interface {
+	RestrictOutputAddrPort(ctx context.Context, addrPort netip.AddrPort) (err error)
+}

internal/dns/logger.go

@@ -1,8 +0,0 @@
-package dns
-
-type Logger interface {
-	Debug(s string)
-	Info(s string)
-	Warn(s string)
-	Error(s string)
-}

internal/dns/loop.go

@@ -24,6 +24,7 @@ type Loop struct {
 	localResolvers []netip.Addr
 	resolvConf     string
 	client         *http.Client
+	firewall       Firewall
 	logger         Logger
 	userTrigger    bool
 	start          <-chan struct{}
@@ -39,7 +40,7 @@ type Loop struct {
 const defaultBackoffTime = 10 * time.Second
 
 func NewLoop(settings settings.DNS,
-	client *http.Client, logger Logger,
+	client *http.Client, firewall Firewall, logger Logger,
 ) (loop *Loop, err error) {
 	start := make(chan struct{})
 	running := make(chan models.LoopStatus)
@@ -64,6 +65,7 @@ func NewLoop(settings settings.DNS,
 		filter:        filter,
 		resolvConf:    "/etc/resolv.conf",
 		client:        client,
+		firewall:      firewall,
 		logger:        logger,
 		userTrigger:   true,
 		start:         start,

internal/dns/plaintext.go

@@ -1,13 +1,14 @@
 package dns
 
 import (
+	"context"
 	"net/netip"
 	"time"
 
 	"github.com/qdm12/dns/v2/pkg/nameserver"
 )
 
-func (l *Loop) useUnencryptedDNS(fallback bool) {
+func (l *Loop) useUnencryptedDNS(ctx context.Context, fallback bool) {
 	settings := l.GetSettings()
 
 	targetIP := settings.GetFirstPlaintextIPv4()
@@ -20,8 +21,9 @@ func (l *Loop) useUnencryptedDNS(fallback bool) {
 
 	const dialTimeout = 3 * time.Second
 	const defaultDNSPort = 53
+	addrPort := netip.AddrPortFrom(targetIP, defaultDNSPort)
 	settingsInternalDNS := nameserver.SettingsInternalDNS{
-		AddrPort: netip.AddrPortFrom(targetIP, defaultDNSPort),
+		AddrPort: addrPort,
 		Timeout:  dialTimeout,
 	}
 	nameserver.UseDNSInternally(settingsInternalDNS)
@@ -34,4 +36,9 @@ func (l *Loop) useUnencryptedDNS(fallback bool) {
 	if err != nil {
 		l.logger.Error(err.Error())
 	}
+
+	err = l.firewall.RestrictOutputAddrPort(ctx, addrPort)
+	if err != nil {
+		l.logger.Error("restricting plain DNS traffic to " + targetIP.String() + ": " + err.Error())
+	}
 }

internal/dns/run.go

@@ -2,6 +2,7 @@ package dns
 
 import (
 	"context"
+	"errors"
 
 	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/gluetun/internal/constants"
@@ -23,7 +24,7 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			"and go through your container network DNS outside the VPN tunnel!")
 	} else {
 		const fallback = false
-		l.useUnencryptedDNS(fallback)
+		l.useUnencryptedDNS(ctx, fallback)
 	}
 
 	select {
@@ -52,6 +53,11 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			if ctx.Err() != nil {
 				return
 			}
+
+			if !errors.Is(err, errUpdateBlockLists) {
+				const fallback = true
+				l.useUnencryptedDNS(ctx, fallback)
+			}
 			l.logAndWait(ctx, err)
 			settings = l.GetSettings()
 		}
@@ -60,7 +66,7 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 		settings = l.GetSettings()
 		if !*settings.KeepNameserver && !*settings.ServerEnabled {
 			const fallback = false
-			l.useUnencryptedDNS(fallback)
+			l.useUnencryptedDNS(ctx, fallback)
 		}
 
 		l.userTrigger = false
@@ -88,7 +94,7 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 			settings := l.GetSettings()
 			if !*settings.KeepNameserver && *settings.ServerEnabled {
 				const fallback = false
-				l.useUnencryptedDNS(fallback)
+				l.useUnencryptedDNS(ctx, fallback)
 				l.stopServer()
 			}
 			l.stopped <- struct{}{}
@@ -99,7 +105,7 @@ func (l *Loop) runWait(ctx context.Context, runError <-chan error) (exitLoop boo
 		case err := <-runError: // unexpected error
 			l.statusManager.SetStatus(constants.Crashed)
 			const fallback = true
-			l.useUnencryptedDNS(fallback)
+			l.useUnencryptedDNS(ctx, fallback)
 			l.logAndWait(ctx, err)
 			return false
 		}

internal/dns/setup.go

@@ -2,28 +2,24 @@ package dns
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net/netip"
 
 	"github.com/qdm12/dns/v2/pkg/check"
-	"github.com/qdm12/dns/v2/pkg/middlewares/filter/update"
 	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/dns/v2/pkg/server"
 )
 
+var errUpdateBlockLists = errors.New("cannot update filter block lists")
+
 func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err error) {
-	settings := l.GetSettings()
-	var updateSettings update.Settings
-	updateSettings.SetRebindingProtectionExempt(settings.Blacklist.RebindingProtectionExemptHostnames)
-	err = l.filter.Update(updateSettings)
+	err = l.updateFiles(ctx)
 	if err != nil {
-		return nil, fmt.Errorf("updating filter for rebinding protection: %w", err)
+		return nil, fmt.Errorf("%w: %w", errUpdateBlockLists, err)
 	}
 
-	err = l.updateFiles(ctx, settings)
-	if err != nil {
-		l.logger.Warn("downloading block lists failed, skipping: " + err.Error())
-	}
+	settings := l.GetSettings()
 
 	serverSettings, err := buildServerSettings(settings, l.filter, l.localResolvers, l.logger)
 	if err != nil {
@@ -43,8 +39,9 @@ func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err erro
 
 	// use internal DNS server
 	const defaultDNSPort = 53
+	addrPort := netip.AddrPortFrom(settings.ServerAddress, defaultDNSPort)
 	nameserver.UseDNSInternally(nameserver.SettingsInternalDNS{
-		AddrPort: netip.AddrPortFrom(settings.ServerAddress, defaultDNSPort),
+		AddrPort: addrPort,
 	})
 	err = nameserver.UseDNSSystemWide(nameserver.SettingsSystemDNS{
 		IPs:        []netip.Addr{settings.ServerAddress},
@@ -54,6 +51,11 @@ func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err erro
 		l.logger.Error(err.Error())
 	}
 
+	err = l.firewall.RestrictOutputAddrPort(ctx, addrPort)
+	if err != nil {
+		l.logger.Error("restricting plain DNS traffic to " + addrPort.Addr().String() + ": " + err.Error())
+	}
+
 	err = check.WaitForDNS(ctx, check.Settings{})
 	if err != nil {
 		l.stopServer()

internal/dns/ticker.go

@@ -30,9 +30,8 @@ func (l *Loop) RunRestartTicker(ctx context.Context, done chan<- struct{}) {
 			lastTick = l.timeNow()
 
 			status := l.GetStatus()
-			settings := l.GetSettings()
 			if status == constants.Running {
-				if err := l.updateFiles(ctx, settings); err != nil {
+				if err := l.updateFiles(ctx); err != nil {
 					l.statusManager.SetStatus(constants.Crashed)
 					l.logger.Error(err.Error())
 					l.logger.Warn("skipping DNS server restart due to failed files update")
@@ -45,6 +44,7 @@ func (l *Loop) RunRestartTicker(ctx context.Context, done chan<- struct{}) {
 			_, _ = l.statusManager.ApplyStatus(ctx, constants.Stopped)
 			_, _ = l.statusManager.ApplyStatus(ctx, constants.Running)
 
+			settings := l.GetSettings()
 			timer.Reset(*settings.UpdatePeriod)
 		case <-l.updateTicker:
 			if !timer.Stop() {

internal/dns/update.go

@@ -6,10 +6,11 @@ import (
 
 	"github.com/qdm12/dns/v2/pkg/blockbuilder"
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/update"
-	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (l *Loop) updateFiles(ctx context.Context, settings settings.DNS) (err error) {
+func (l *Loop) updateFiles(ctx context.Context) (err error) {
+	settings := l.GetSettings()
+
 	l.logger.Info("downloading hostnames and IP block lists")
 	blacklistSettings := settings.Blacklist.ToBlockBuilderSettings(l.client)
 
@@ -36,6 +37,7 @@ func (l *Loop) updateFiles(ctx context.Context, settings settings.DNS) (err erro
 		IPPrefixes: result.BlockedIPPrefixes,
 	}
 	updateSettings.BlockHostnames(result.BlockedHostnames)
+	updateSettings.SetRebindingProtectionExempt(settings.Blacklist.RebindingProtectionExemptHostnames)
 	err = l.filter.Update(updateSettings)
 	if err != nil {
 		return fmt.Errorf("updating filter: %w", err)

internal/firewall/delete_test.go

@@ -69,8 +69,8 @@ func Test_deleteIPTablesRule(t *testing.T) {
 		"invalid_instruction": {
 			instruction: "invalid",
 			errWrapped:  ErrIptablesCommandMalformed,
-			errMessage: "parsing iptables command: iptables command is malformed: " +
-				"fields count 1 is not even: \"invalid\"",
+			errMessage: "parsing iptables command: parsing \"invalid\": " +
+				"iptables command is malformed: flag \"invalid\" requires a value, but got none",
 		},
 		"list_error": {
 			instruction: "-t nat --delete PREROUTING -i tun0 -p tcp --dport 43716 -j REDIRECT --to-ports 5678",

internal/firewall/firewall.go

@@ -13,6 +13,7 @@ type Config struct {
 	runner         CmdRunner
 	logger         Logger
 	iptablesMutex  sync.Mutex
+	ip6tablesMutex sync.Mutex
 	defaultRoutes  []routing.DefaultRoute
 	localNetworks  []routing.LocalNetwork
 
@@ -28,6 +29,7 @@ type Config struct {
 	outboundSubnets   []netip.Prefix
 	allowedInputPorts map[uint16]map[string]struct{} // port to interfaces set mapping
 	portRedirections  portRedirections
+	outputAddrPort    map[uint16]netip.Addr
 	stateMutex        sync.Mutex
 }
 
@@ -51,6 +53,7 @@ func NewConfig(ctx context.Context, logger Logger,
 		runner:            runner,
 		logger:            logger,
 		allowedInputPorts: make(map[uint16]map[string]struct{}),
+		outputAddrPort:    make(map[uint16]netip.Addr),
 		ipTables:          iptables,
 		ip6Tables:         ip6tables,
 		customRulesPath:   "/iptables/post-rules.txt",

internal/firewall/ip6tables.go

@@ -36,8 +36,8 @@ func (c *Config) runIP6tablesInstruction(ctx context.Context, instruction string
 	if c.ip6Tables == "" {
 		return nil
 	}
-	c.iptablesMutex.Lock() // only one ip6tables command at once
-	defer c.iptablesMutex.Unlock()
+	c.ip6tablesMutex.Lock() // only one ip6tables command at once
+	defer c.ip6tablesMutex.Unlock()
 
 	if isDeleteMatchInstruction(instruction) {
 		return deleteIPTablesRule(ctx, c.ip6Tables, instruction,

internal/firewall/iptables.go

@@ -148,6 +148,9 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 	defaultInterface string, connection models.Connection, remove bool,
 ) error {
 	protocol := connection.Protocol
+	if protocol == "tcp-client" {
+		protocol = "tcp"
+	}
 	instruction := fmt.Sprintf("%s OUTPUT -d %s -o %s -p %s -m %s --dport %d -j ACCEPT",
 		appendOrDelete(remove), connection.IP, defaultInterface, protocol,
 		protocol, connection.Port)
@@ -215,9 +218,6 @@ func (c *Config) redirectPort(ctx context.Context, intf string,
 		interfaceFlag = ""
 	}
 
-	c.iptablesMutex.Lock()
-	defer c.iptablesMutex.Unlock()
-
 	err = c.runIptablesInstructions(ctx, []string{
 		fmt.Sprintf("-t nat %s PREROUTING %s -p tcp --dport %d -j REDIRECT --to-ports %d",
 			appendOrDelete(remove), interfaceFlag, sourcePort, destinationPort),

internal/firewall/iptablesmix.go

@@ -2,6 +2,7 @@ package firewall
 
 import (
 	"context"
+	"fmt"
 )
 
 func (c *Config) runMixedIptablesInstructions(ctx context.Context, instructions []string) error {
@@ -19,3 +20,15 @@ func (c *Config) runMixedIptablesInstruction(ctx context.Context, instruction st
 	}
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
+
+func (c *Config) runIPv4AndV6IptablesInstructions(ctx context.Context,
+	ipv4Instructions, ipv6Instructions []string,
+) error {
+	if err := c.runIptablesInstructions(ctx, ipv4Instructions); err != nil {
+		return fmt.Errorf("running iptables instructions: %w", err)
+	}
+	if err := c.runIP6tablesInstructions(ctx, ipv6Instructions); err != nil {
+		return fmt.Errorf("running ip6tables instructions: %w", err)
+	}
+	return nil
+}

internal/firewall/parse.go

@@ -9,9 +9,19 @@ import (
 	"strings"
 )
 
+type operation uint8
+
+const (
+	opNone operation = iota
+	opAppend
+	opDelete
+	opInsert
+	opReplace
+)
+
 type iptablesInstruction struct {
 	table           string // defaults to "filter", and can be "nat" for example.
-	append          bool
+	operation       operation
 	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.
@@ -22,6 +32,7 @@ type iptablesInstruction struct {
 	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
+	lineNumber      uint16       // for replace operation, the line number to replace
 }
 
 func (i *iptablesInstruction) setDefaults() {
@@ -60,6 +71,58 @@ func (i *iptablesInstruction) equalToRule(table, chain string, rule chainRule) (
 	}
 }
 
+func (i *iptablesInstruction) String() string {
+	var sb strings.Builder
+	if i.table != "" && i.table != "filter" {
+		sb.WriteString(fmt.Sprintf("-t %s ", i.table))
+	}
+	switch i.operation {
+	case opNone:
+		panic("no operation specified")
+	case opAppend:
+		sb.WriteString(fmt.Sprintf("--append %s ", i.chain))
+	case opDelete:
+		sb.WriteString(fmt.Sprintf("--delete %s ", i.chain))
+	case opInsert:
+		sb.WriteString(fmt.Sprintf("--insert %s ", i.chain))
+	case opReplace:
+		sb.WriteString(fmt.Sprintf("--replace %s %d ", i.chain, i.lineNumber))
+	}
+	if i.inputInterface != "" {
+		sb.WriteString(fmt.Sprintf("-i %s ", i.inputInterface))
+	}
+	if i.outputInterface != "" {
+		sb.WriteString(fmt.Sprintf("-o %s ", i.outputInterface))
+	}
+	if i.protocol != "" {
+		sb.WriteString(fmt.Sprintf("-p %s ", i.protocol))
+	}
+	if i.source.IsValid() {
+		sb.WriteString(fmt.Sprintf("-s %s ", i.source.String()))
+	}
+	if i.destination.IsValid() {
+		sb.WriteString(fmt.Sprintf("-d %s ", i.destination.String()))
+	}
+	if i.destinationPort != 0 {
+		sb.WriteString(fmt.Sprintf("--dport %d ", i.destinationPort))
+	}
+	if len(i.ctstate) > 0 {
+		sb.WriteString(fmt.Sprintf("--ctstate %s ", strings.Join(i.ctstate, ",")))
+	}
+	if len(i.toPorts) > 0 {
+		var portStrings []string
+		for _, port := range i.toPorts {
+			portStrings = append(portStrings, strconv.FormatUint(uint64(port), 10))
+		}
+		sb.WriteString(fmt.Sprintf("--to-ports %s ", strings.Join(portStrings, ",")))
+	}
+	if i.target != "" {
+		sb.WriteString(fmt.Sprintf("-j %s ", i.target))
+	}
+
+	return strings.TrimSpace(sb.String())
+}
+
 // instruction can be "" which equivalent to the "*" chain rule interface.
 func networkInterfacesEqual(instruction, chainRule string) bool {
 	return instruction == chainRule || (instruction == "" && chainRule == "*")
@@ -77,34 +140,63 @@ func parseIptablesInstruction(s string) (instruction iptablesInstruction, err er
 		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)
+	i := 0
+	for i < len(fields) {
+		consumed, err := parseInstructionFlag(fields[i:], &instruction)
 		if err != nil {
 			return iptablesInstruction{}, fmt.Errorf("parsing %q: %w", s, err)
 		}
+		i += consumed
 	}
 
 	instruction.setDefaults()
 	return instruction, nil
 }
 
-func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (err error) {
-	switch key {
+func parseInstructionFlag(fields []string, instruction *iptablesInstruction) (consumed int, err error) {
+	flag := fields[0]
+
+	// All flags use one value after the flag, except the following:
+	switch flag {
+	case "-R", "--replace":
+		const expected = 3
+		if len(fields) < expected {
+			return 0, fmt.Errorf("%w: flag %q requires at least 2 values, but got %s",
+				ErrIptablesCommandMalformed, flag, strings.Join(fields, " "))
+		}
+		consumed = expected
+	default:
+		const expected = 2
+		if len(fields) < expected {
+			return 0, fmt.Errorf("%w: flag %q requires a value, but got none",
+				ErrIptablesCommandMalformed, flag)
+		}
+		consumed = expected
+	}
+	value := fields[1]
+
+	switch flag {
 	case "-t", "--table":
 		instruction.table = value
 	case "-D", "--delete":
-		instruction.append = false
+		instruction.operation = opDelete
 		instruction.chain = value
 	case "-A", "--append":
-		instruction.append = true
+		instruction.operation = opAppend
 		instruction.chain = value
+	case "-I", "--insert":
+		instruction.operation = opInsert
+		instruction.chain = value
+	case "-R", "--replace":
+		instruction.operation = opReplace
+		instruction.chain = value
+		const base, bits = 10, 16
+		n, err := strconv.ParseUint(fields[2], base, bits)
+		if err != nil {
+			return 0, fmt.Errorf("parsing line number for --replace operation: %w", err)
+		}
+		instruction.lineNumber = uint16(n)
 	case "-j", "--jump":
 		instruction.target = value
 	case "-p", "--protocol":
@@ -117,18 +209,18 @@ func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (
 	case "-s", "--source":
 		instruction.source, err = parseIPPrefix(value)
 		if err != nil {
-			return fmt.Errorf("parsing source IP CIDR: %w", err)
+			return 0, 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)
+			return 0, 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)
+			return 0, fmt.Errorf("parsing destination port: %w", err)
 		}
 		instruction.destinationPort = uint16(destinationPort)
 	case "--ctstate":
@@ -140,14 +232,14 @@ func parseInstructionFlag(key, value string, instruction *iptablesInstruction) (
 			const base, bitLength = 10, 16
 			port, err := strconv.ParseUint(portString, base, bitLength)
 			if err != nil {
-				return fmt.Errorf("parsing port redirection: %w", err)
+				return 0, fmt.Errorf("parsing port redirection: %w", err)
 			}
 			instruction.toPorts[i] = uint16(port)
 		}
 	default:
-		return fmt.Errorf("%w: unknown key %q", ErrIptablesCommandMalformed, key)
+		return 0, fmt.Errorf("%w: unknown flag %q", ErrIptablesCommandMalformed, flag)
 	}
-	return nil
+	return consumed, nil
 }
 
 func parseIPPrefix(value string) (prefix netip.Prefix, err error) {

internal/firewall/parse_test.go

@@ -23,19 +23,19 @@ func Test_parseIptablesInstruction(t *testing.T) {
 		"uneven_fields": {
 			s:          "-A",
 			errWrapped: ErrIptablesCommandMalformed,
-			errMessage: "iptables command is malformed: fields count 1 is not even: \"-A\"",
+			errMessage: "parsing \"-A\": iptables command is malformed: flag \"-A\" requires a value, but got none",
 		},
 		"unknown_key": {
 			s:          "-x something",
 			errWrapped: ErrIptablesCommandMalformed,
-			errMessage: "parsing \"-x something\": iptables command is malformed: unknown key \"-x\"",
+			errMessage: "parsing \"-x something\": iptables command is malformed: unknown flag \"-x\"",
 		},
 		"one_pair": {
-			s: "-A INPUT",
+			s: "-I INPUT",
 			instruction: iptablesInstruction{
 				table:     "filter",
 				chain:     "INPUT",
-				append: true,
+				operation: opInsert,
 			},
 		},
 		"instruction_A": {
@@ -43,7 +43,7 @@ func Test_parseIptablesInstruction(t *testing.T) {
 			instruction: iptablesInstruction{
 				table:           "filter",
 				chain:           "INPUT",
-				append:          true,
+				operation:       opAppend,
 				inputInterface:  "tun0",
 				protocol:        "tcp",
 				source:          netip.MustParsePrefix("1.2.3.4/32"),
@@ -57,7 +57,7 @@ func Test_parseIptablesInstruction(t *testing.T) {
 			instruction: iptablesInstruction{
 				table:           "nat",
 				chain:           "PREROUTING",
-				append:          false,
+				operation:       opDelete,
 				inputInterface:  "tun0",
 				protocol:        "tcp",
 				destinationPort: 43716,

internal/firewall/ports.go

@@ -3,6 +3,7 @@ package firewall
 import (
 	"context"
 	"fmt"
+	"net/netip"
 	"strconv"
 )
 
@@ -81,3 +82,133 @@ func (c *Config) RemoveAllowedPort(ctx context.Context, port uint16) (err error)
 
 	return nil
 }
+
+// RestrictOutputAddrPort allows outgoing traffic to a specific IP and port for both tcp and udp,
+// while blocking other tcp or udp traffic to that port going to other IP addresses, both IPv4 and IPv6.
+// If the port was previously allowed for another IP address, that previous allowance will be removed.
+// Giving an invalid address will remove any existing restrictions for the port specified.
+func (c *Config) RestrictOutputAddrPort(ctx context.Context, addrPort netip.AddrPort) (err error) {
+	c.stateMutex.Lock()
+	defer c.stateMutex.Unlock()
+	existingIP := c.outputAddrPort[addrPort.Port()]
+
+	switch {
+	case existingIP == addrPort.Addr():
+		return nil
+	case !addrPort.Addr().IsValid():
+		// invalid address, remove any existing rules for the port
+		return c.removeOutputAddrPortRestriction(ctx, existingIP, addrPort.Port())
+	case !existingIP.IsValid():
+		// no previous existing address for the port
+		return c.insertOutputAddrPortRestriction(ctx, addrPort)
+	default:
+		// existing rule in the same IP family or different family
+		return c.replaceOutputAddrPortRestriction(ctx, existingIP, addrPort)
+	}
+}
+
+func (c *Config) removeOutputAddrPortRestriction(ctx context.Context, existingIP netip.Addr, port uint16) (err error) {
+	commonInstructions := []string{
+		fmt.Sprintf("--delete OUTPUT -p udp --dport %d -j DROP", port),
+		fmt.Sprintf("--delete OUTPUT -p tcp --dport %d -j DROP", port),
+	}
+	ipv4Instructions := commonInstructions
+	ipv6Instructions := commonInstructions
+
+	familySpecificInstructions := []string{
+		fmt.Sprintf("--delete OUTPUT -p udp --dport %d -d %s -j ACCEPT", port, existingIP),
+		fmt.Sprintf("--delete OUTPUT -p tcp --dport %d -d %s -j ACCEPT", port, existingIP),
+	}
+	if existingIP.Is4() {
+		ipv4Instructions = append(ipv4Instructions, familySpecificInstructions...)
+	} else {
+		ipv6Instructions = append(ipv6Instructions, familySpecificInstructions...)
+	}
+
+	err = c.runIPv4AndV6IptablesInstructions(ctx, ipv4Instructions, ipv6Instructions)
+	if err != nil {
+		return err
+	}
+	delete(c.outputAddrPort, port)
+	return nil
+}
+
+func (c *Config) insertOutputAddrPortRestriction(ctx context.Context, addrPort netip.AddrPort) (err error) {
+	commonInstructions := []string{
+		fmt.Sprintf("--insert OUTPUT -p udp --dport %d -j DROP", addrPort.Port()),
+		fmt.Sprintf("--insert OUTPUT -p tcp --dport %d -j DROP", addrPort.Port()),
+	}
+	ipv4Instructions := commonInstructions
+	ipv6Instructions := commonInstructions
+
+	familySpecificInstructions := []string{
+		fmt.Sprintf("--insert OUTPUT -p udp --dport %d -d %s -j ACCEPT", addrPort.Port(), addrPort.Addr()),
+		fmt.Sprintf("--insert OUTPUT -p tcp --dport %d -d %s -j ACCEPT", addrPort.Port(), addrPort.Addr()),
+	}
+	if addrPort.Addr().Is4() {
+		ipv4Instructions = append(ipv4Instructions, familySpecificInstructions...)
+	} else {
+		ipv6Instructions = append(ipv6Instructions, familySpecificInstructions...)
+	}
+	err = c.runIPv4AndV6IptablesInstructions(ctx, ipv4Instructions, ipv6Instructions)
+	if err != nil {
+		return err
+	}
+	c.outputAddrPort[addrPort.Port()] = addrPort.Addr()
+	return nil
+}
+
+func (c *Config) replaceOutputAddrPortRestriction(ctx context.Context,
+	existingIP netip.Addr, addrPort netip.AddrPort,
+) (err error) {
+	for _, protocol := range [...]string{"udp", "tcp"} {
+		switch {
+		case existingIP.Is4() && addrPort.Addr().Is4():
+			oldInstruction := fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), existingIP)
+			newInstruction := fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), addrPort.Addr())
+			err = c.replaceIptablesRule(ctx, oldInstruction, newInstruction)
+			if err != nil {
+				return fmt.Errorf("replacing existing IPv4 rule: %w", err)
+			}
+		case existingIP.Is6() && addrPort.Addr().Is6():
+			oldInstruction := fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), existingIP)
+			newInstruction := fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), addrPort.Addr())
+			err = c.replaceIP6tablesRule(ctx, oldInstruction, newInstruction)
+			if err != nil {
+				return fmt.Errorf("replacing existing IPv6 rule: %w", err)
+			}
+		case existingIP.Is4() && addrPort.Addr().Is6():
+			instruction := fmt.Sprintf("--delete OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), existingIP)
+			err = c.runIptablesInstruction(ctx, instruction)
+			if err != nil {
+				return fmt.Errorf("removing existing IPv4 rule: %w", err)
+			}
+			instruction = fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), addrPort.Addr())
+			err = c.runIP6tablesInstruction(ctx, instruction)
+			if err != nil {
+				return fmt.Errorf("inserting new IPv6 rule: %w", err)
+			}
+		case existingIP.Is6() && addrPort.Addr().Is4():
+			instruction := fmt.Sprintf("--delete OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), existingIP)
+			err = c.runIP6tablesInstruction(ctx, instruction)
+			if err != nil {
+				return fmt.Errorf("removing existing IPv6 rule: %w", err)
+			}
+			instruction = fmt.Sprintf("--insert OUTPUT -p %s --dport %d -d %s -j ACCEPT",
+				protocol, addrPort.Port(), addrPort.Addr())
+			err = c.runIptablesInstruction(ctx, instruction)
+			if err != nil {
+				return fmt.Errorf("inserting new IPv4 rule: %w", err)
+			}
+		}
+	}
+	c.outputAddrPort[addrPort.Port()] = addrPort.Addr()
+	return nil
+}

internal/firewall/replace.go

@@ -0,0 +1,51 @@
+package firewall
+
+import (
+	"context"
+	"errors"
+	"fmt"
+)
+
+var errRuleNotFound = errors.New("rule not found")
+
+func (c *Config) replaceIptablesRule(ctx context.Context, oldInstruction, newInstruction string) error {
+	targetRule, err := parseIptablesInstruction(oldInstruction)
+	if err != nil {
+		return fmt.Errorf("parsing iptables command to replace: %w", err)
+	}
+
+	lineNumber, err := findLineNumber(ctx, c.ipTables, targetRule, c.runner, c.logger)
+	if err != nil {
+		return fmt.Errorf("finding to-be-replaced chain rule line number: %w", err)
+	} else if lineNumber == 0 {
+		return fmt.Errorf("%w: matching to-be-replaced instruction %q", errRuleNotFound, oldInstruction)
+	}
+	parsed, err := parseIptablesInstruction(newInstruction)
+	if err != nil {
+		return fmt.Errorf("parsing replacement iptables command: %w", err)
+	}
+	parsed.operation = opReplace
+	parsed.lineNumber = lineNumber
+	return c.runIptablesInstruction(ctx, parsed.String())
+}
+
+func (c *Config) replaceIP6tablesRule(ctx context.Context, oldInstruction, newInstruction string) error {
+	targetRule, err := parseIptablesInstruction(oldInstruction)
+	if err != nil {
+		return fmt.Errorf("parsing iptables command to replace: %w", err)
+	}
+
+	lineNumber, err := findLineNumber(ctx, c.ip6Tables, targetRule, c.runner, c.logger)
+	if err != nil {
+		return fmt.Errorf("finding to-be-replaced chain rule line number: %w", err)
+	} else if lineNumber == 0 {
+		return fmt.Errorf("%w: matching to-be-replaced instruction %q", errRuleNotFound, oldInstruction)
+	}
+	parsed, err := parseIptablesInstruction(newInstruction)
+	if err != nil {
+		return fmt.Errorf("parsing replacement iptables command: %w", err)
+	}
+	parsed.operation = opReplace
+	parsed.lineNumber = lineNumber
+	return c.runIP6tablesInstruction(ctx, parsed.String())
+}

internal/healthcheck/checker.go

@@ -8,6 +8,7 @@ import (
 	"net"
 	"net/netip"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/qdm12/gluetun/internal/healthcheck/dns"
@@ -22,7 +23,7 @@ type Checker struct {
 	logger         Logger
 	icmpTargetIPs  []netip.Addr
 	smallCheckType string
-	startupOnFail  bool
+	configMutex    sync.Mutex
 
 	icmpNotPermitted *bool
 
@@ -44,41 +45,26 @@ func NewChecker(logger Logger) *Checker {
 	}
 }
 
-// SetConfig sets the following:
-// - TCP+TLS dial addresses
-// - ICMP echo IP addresses to target
-// - the desired small check type (dns or icmp)
-// - whether to startup the periodic checks if the startup check fails.
+// SetConfig sets the TCP+TLS dial addresses, the ICMP echo IP address
+// to target and the desired small check type (dns or icmp).
 // This function MUST be called before calling [Checker.Start].
 func (c *Checker) SetConfig(tlsDialAddrs []string, icmpTargets []netip.Addr,
-	smallCheckType string, startupOnFail bool,
+	smallCheckType string,
 ) {
+	c.configMutex.Lock()
+	defer c.configMutex.Unlock()
 	c.tlsDialAddrs = tlsDialAddrs
 	c.icmpTargetIPs = icmpTargets
 	c.smallCheckType = smallCheckType
-	c.startupOnFail = startupOnFail
 }
 
-// Start starts the [Checker] which behaves differently according to its
-// internal field startupOnFail, which is set by calling [Checker.SetConfig].
-//
-// By default, startupOnFail should be false and the behavior is as follows:
-// A blocking 6s-timed TCP+TLS check is performed first. If it fails,
-// an error is returned and the [Checker] is not started.
-// On success, it starts the periodic checks in a separate goroutine, returning
-// the runError error channel and a nil error.
-//
-// If startupOnFail is true, the behavior is as follows:
-// A blocking 6s-timed TCP+TLS check is performed first. If it fails,
-// the error is sent to the runError channel, but no error is returned
-// and the [Checker] continues to start the periodic checks in a separate goroutine, returning
-// the runError error channel and a nil error.
-//
-// The periodic checks consist in:
+// Start starts the checker by first running a blocking 6s-timed TCP+TLS check,
+// and, on success, starts the periodic checks in a separate goroutine:
 // - a "small" ICMP echo check every minute
 // - a "full" TCP+TLS check every 5 minutes
-//
-// The [Checker] has to be ultimately stopped by calling [Checker.Stop].
+// It returns a channel `runError` that receives an error (nil or not) when a periodic check is performed.
+// It returns an error if the initial TCP+TLS check fails.
+// The Checker has to be ultimately stopped by calling [Checker.Stop].
 func (c *Checker) Start(ctx context.Context) (runError <-chan error, err error) {
 	if len(c.tlsDialAddrs) == 0 || len(c.icmpTargetIPs) == 0 || c.smallCheckType == "" {
 		panic("call Checker.SetConfig with non empty values before Checker.Start")
@@ -90,19 +76,9 @@ func (c *Checker) Start(ctx context.Context) (runError <-chan error, err error)
 	}
 	c.echoer.Reset()
 
-	// runErrorCh MUST be buffered in the case startupOnFail is true, and
-	// a startup error was encountered, to avoid blocking the startup
-	// goroutine when sending the error, especially since the caller may
-	// not be ready to receive from the channel yet.
-	runErrorCh := make(chan error, 1)
-	runError = runErrorCh
 	err = c.startupCheck(ctx)
 	if err != nil {
-		err = fmt.Errorf("startup check: %w", err)
-		if !c.startupOnFail {
-			return nil, err
-		}
-		runErrorCh <- err
+		return nil, fmt.Errorf("startup check: %w", err)
 	}
 
 	ready := make(chan struct{})
@@ -114,6 +90,8 @@ func (c *Checker) Start(ctx context.Context) (runError <-chan error, err error)
 	smallCheckTimer := time.NewTimer(smallCheckPeriod)
 	const fullCheckPeriod = 5 * time.Minute
 	fullCheckTimer := time.NewTimer(fullCheckPeriod)
+	runErrorCh := make(chan error)
+	runError = runErrorCh
 	go func() {
 		defer close(done)
 		close(ready)
@@ -162,8 +140,10 @@ func (c *Checker) Stop() error {
 }
 
 func (c *Checker) smallPeriodicCheck(ctx context.Context) error {
+	c.configMutex.Lock()
 	icmpTargetIPs := make([]netip.Addr, len(c.icmpTargetIPs))
 	copy(icmpTargetIPs, c.icmpTargetIPs)
+	c.configMutex.Unlock()
 	tryTimeouts := []time.Duration{
 		5 * time.Second,
 		5 * time.Second,

internal/healthcheck/client.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"time"
 )
 
 var ErrHTTPStatusNotOK = errors.New("HTTP response status is not OK")
@@ -22,9 +21,6 @@ func NewClient(httpClient *http.Client) *Client {
 }
 
 func (c *Client) Check(ctx context.Context, url string) error {
-	ctx, cancel := context.WithTimeout(ctx, time.Second)
-	defer cancel()
-
 	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
 		return err

internal/mod/builtin_linux.go

@@ -1,33 +0,0 @@
-package mod
-
-import (
-	"bufio"
-	"errors"
-	"fmt"
-	"os"
-	"path/filepath"
-	"strings"
-)
-
-var errBuiltinModuleNotFound = errors.New("builtin module not found")
-
-func checkModulesBuiltin(modulesPath, moduleName string) error {
-	f, err := os.Open(filepath.Join(modulesPath, "modules.builtin"))
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	moduleName = strings.TrimSuffix(moduleName, ".ko")
-
-	scanner := bufio.NewScanner(f)
-	for scanner.Scan() {
-		line := scanner.Text()
-		line = strings.TrimSuffix(line, ".ko")
-		if strings.HasSuffix(line, "/"+moduleName) {
-			return nil
-		}
-	}
-
-	return fmt.Errorf("%w: %s", errBuiltinModuleNotFound, moduleName)
-}

internal/mod/configgz_linux.go

@@ -1,132 +0,0 @@
-package mod
-
-import (
-	"bufio"
-	"compress/gzip"
-	"errors"
-	"fmt"
-	"os"
-	"strings"
-)
-
-var (
-	errModuleNameUnknown     = errors.New("unknown module name")
-	errKernelFeatureIsModule = errors.New("kernel feature is a module, not built-in")
-	errKernelFeatureNotSet   = errors.New("kernel feature not set")
-	errKernelFeatureNotFound = errors.New("kernel feature not found")
-)
-
-// checkProcConfig checks /proc/config.gz for a the kernel feature corresponding
-// to the given module name. If the kernel feature is found and set to "y", it returns nil.
-// If the kernel feature is found and set to "m", it returns an error indicating that the kernel
-// feature is a module, not built-in.
-// If the kernel feature is found and not set, it returns an error indicating that the kernel
-// feature is not set. If the kernel feature is not found, it returns an error indicating that the kernel
-// feature is not found.
-func checkProcConfig(moduleName string) error {
-	f, err := os.Open("/proc/config.gz")
-	if err != nil {
-		return err
-	}
-	defer f.Close()
-
-	gz, err := gzip.NewReader(f)
-	if err != nil {
-		return fmt.Errorf("creating gzip reader: %w", err)
-	}
-	defer gz.Close()
-
-	// If any group of kernel features is satisfied, then the module is considered supported.
-	kernelFeatureGroups, ok := moduleNameToKernelFeatureGroups(moduleName)
-	if !ok {
-		return fmt.Errorf("%w: %s", errModuleNameUnknown, moduleName)
-	}
-	groups := make([]map[string]bool, len(kernelFeatureGroups))
-	for i, group := range kernelFeatureGroups {
-		featureToOK := make(map[string]bool)
-		for _, feature := range group {
-			featureToOK[feature] = false
-		}
-		groups[i] = featureToOK
-	}
-
-	scanner := bufio.NewScanner(gz)
-	for scanner.Scan() {
-		line := scanner.Text()
-		for _, featureToOK := range groups {
-			for name, ok := range featureToOK {
-				switch {
-				case ok:
-				case strings.HasPrefix(line, name+"=m"):
-					return fmt.Errorf("%w: %s", errKernelFeatureIsModule, name)
-				case strings.HasPrefix(line, name+"=y"):
-					featureToOK[name] = true
-					if allFeaturesOK(featureToOK) {
-						return nil
-					}
-				case strings.HasPrefix(line, "# "+name+" is not set"):
-					return fmt.Errorf("%w: %s", errKernelFeatureNotSet, name)
-				}
-			}
-		}
-	}
-
-	return fmt.Errorf("%w: for module name %s", errKernelFeatureNotFound, moduleName)
-}
-
-func moduleNameToKernelFeatureGroups(moduleName string) (featureGroups [][]string, ok bool) {
-	moduleMap := map[string][][]string{
-		"nf_tables": {{"CONFIG_NF_TABLES"}},
-
-		// Netfilter Matches
-		"xt_conntrack": {{"CONFIG_NETFILTER_XT_MATCH_CONNTRACK"}},
-		"xt_connmark": {
-			{"CONFIG_NETFILTER_XT_CONNMARK"},
-			{"CONFIG_NETFILTER_XT_MATCH_CONNMARK", "CONFIG_NETFILTER_XT_TARGET_CONNMARK"},
-		},
-		"xt_mark": {
-			{"CONFIG_NETFILTER_XT_MARK"},
-			{"CONFIG_NETFILTER_XT_MATCH_MARK", "CONFIG_NETFILTER_XT_TARGET_MARK"},
-		},
-		"nf_conntrack_netlink": {{"CONFIG_NF_CT_NETLINK"}},
-		"nf_reject_ipv4":       {{"CONFIG_NF_REJECT_IPV4"}},
-
-		// Common Netfilter Targets
-		"xt_log": {{"CONFIG_NETFILTER_XT_TARGET_LOG"}},
-		"xt_reject": {
-			{"CONFIG_IP_NF_TARGET_REJECT", "CONFIG_NF_REJECT_IPV4"},
-			{"CONFIG_NETFILTER_XT_TARGET_REJECT", "CONFIG_NF_REJECT_IPV4"},
-		},
-		"xt_masquerade": {{"CONFIG_NETFILTER_XT_TARGET_MASQUERADE"}},
-
-		// Additional Netfilter Matches
-		"xt_addrtype":  {{"CONFIG_NETFILTER_XT_MATCH_ADDRTYPE"}},
-		"xt_comment":   {{"CONFIG_NETFILTER_XT_MATCH_COMMENT"}},
-		"xt_multiport": {{"CONFIG_NETFILTER_XT_MATCH_MULTIPORT"}},
-		"xt_state":     {{"CONFIG_NETFILTER_XT_MATCH_STATE"}},
-		"xt_tcpudp":    {{"CONFIG_NETFILTER_XT_MATCH_TCPUDP"}},
-
-		// Tunneling and Virtualization
-		"tun":       {{"CONFIG_TUN"}},
-		"bridge":    {{"CONFIG_BRIDGE"}},
-		"veth":      {{"CONFIG_VETH"}},
-		"vxlan":     {{"CONFIG_VXLAN"}},
-		"wireguard": {{"CONFIG_WIREGUARD"}},
-
-		// Filesystems
-		"overlay": {{"CONFIG_OVERLAY_FS"}},
-		"fuse":    {{"CONFIG_FUSE_FS"}},
-	}
-
-	featureGroups, ok = moduleMap[strings.ToLower(moduleName)]
-	return featureGroups, ok
-}
-
-func allFeaturesOK(featureToOK map[string]bool) bool {
-	for _, ok := range featureToOK {
-		if !ok {
-			return false
-		}
-	}
-	return true
-}

internal/mod/info_linux.go

@@ -1,3 +1,5 @@
+//go:build !windows
+
 package mod
 
 import (
@@ -28,7 +30,36 @@ type moduleInfo struct {
 
 var ErrModulesDirectoryNotFound = errors.New("modules directory not found")
 
-func getModulesInfo(modulesPath string) (modulesInfo map[string]moduleInfo, err error) {
+func getModulesInfo() (modulesInfo map[string]moduleInfo, err error) {
+	var utsName unix.Utsname
+	err = unix.Uname(&utsName)
+	if err != nil {
+		return nil, fmt.Errorf("getting unix uname release: %w", err)
+	}
+	release := unix.ByteSliceToString(utsName.Release[:])
+	release = strings.TrimSpace(release)
+
+	modulePaths := []string{
+		filepath.Join("/lib/modules", release),
+		filepath.Join("/usr/lib/modules", release),
+	}
+
+	var modulesPath string
+	var found bool
+	for _, modulesPath = range modulePaths {
+		info, err := os.Stat(modulesPath)
+		if err == nil && info.IsDir() {
+			found = true
+			break
+		}
+	}
+
+	if !found {
+		return nil, fmt.Errorf("%w: %s are not valid existing directories"+
+			"; have you bind mounted the /lib/modules directory?",
+			ErrModulesDirectoryNotFound, strings.Join(modulePaths, ", "))
+	}
+
 	dependencyFilepath := filepath.Join(modulesPath, "modules.dep")
 	dependencyFile, err := os.Open(dependencyFilepath)
 	if err != nil {
@@ -80,39 +111,6 @@ func getModulesInfo(modulesPath string) (modulesInfo map[string]moduleInfo, err
 	return modulesInfo, nil
 }
 
-func getModulesPath() (string, error) {
-	release, err := getReleaseName()
-	if err != nil {
-		return "", fmt.Errorf("getting release name: %w", err)
-	}
-
-	modulePaths := []string{
-		filepath.Join("/lib/modules", release),
-		filepath.Join("/usr/lib/modules", release),
-	}
-
-	for _, modulesPath := range modulePaths {
-		info, err := os.Stat(modulesPath)
-		if err == nil && info.IsDir() {
-			return modulesPath, nil
-		}
-	}
-	return "", fmt.Errorf("%w: %s are not valid existing directories"+
-		"; have you bind mounted the /lib/modules directory?",
-		ErrModulesDirectoryNotFound, strings.Join(modulePaths, ", "))
-}
-
-func getReleaseName() (release string, err error) {
-	var utsName unix.Utsname
-	err = unix.Uname(&utsName)
-	if err != nil {
-		return "", fmt.Errorf("getting unix uname release: %w", err)
-	}
-	release = unix.ByteSliceToString(utsName.Release[:])
-	release = strings.TrimSpace(release)
-	return release, nil
-}
-
 func getBuiltinModules(modulesDirPath string, modulesInfo map[string]moduleInfo) error {
 	file, err := os.Open(filepath.Join(modulesDirPath, "modules.builtin"))
 	if err != nil {

internal/mod/probe.go

@@ -1,74 +0,0 @@
-package mod
-
-import (
-	"errors"
-	"fmt"
-)
-
-// Probe is a expanded version of modprobe, in which it checks if the Kernel
-// built-in features contain the given module name.
-// It first tries to locate the modules directory in [getModulesPath].
-// If it fails (like on WSL), it then only checks for the kernel feature
-// in /proc/config.gz with [checkProcConfig].
-// Otherwise, it first checks if the modules directory modules.builtin
-// file contains the given module name in [checkModulesBuiltin].
-// If the module is not found, it then runs the classic [modProbe] behavior,
-// trying to load the module in the kernel.
-// If this fails, it does one final try running [checkProcConfig].
-func Probe(moduleName string) error {
-	modulesPath, err := getModulesPath()
-	if err != nil {
-		if errors.Is(err, ErrModulesDirectoryNotFound) {
-			err = checkProcConfig(moduleName)
-			if err != nil {
-				return fmt.Errorf("checking /proc/config.gz: %w", err)
-			}
-			return nil
-		}
-		return fmt.Errorf("getting modules path: %w", err)
-	}
-
-	err = checkModulesBuiltin(modulesPath, moduleName)
-	if err != nil {
-		err = modProbe(modulesPath, moduleName)
-		if err != nil {
-			err = checkProcConfig(moduleName)
-			if err != nil {
-				return fmt.Errorf("checking /proc/config.gz: %w", err)
-			}
-		}
-	}
-	return nil
-}
-
-// modProbe is the classic modprobe behavior.
-func modProbe(modulesPath, moduleName string) error {
-	modulesInfo, err := getModulesInfo(modulesPath)
-	if err != nil {
-		return fmt.Errorf("getting modules information: %w", err)
-	}
-
-	modulePath, err := findModulePath(moduleName, modulesInfo)
-	if err != nil {
-		return fmt.Errorf("finding module path: %w", err)
-	}
-
-	info := modulesInfo[modulePath]
-	if info.state == builtin || info.state == loaded {
-		return nil
-	}
-
-	info.state = loading
-	for _, dependencyModulePath := range info.dependencyPaths {
-		err = initDependencies(dependencyModulePath, modulesInfo)
-		if err != nil {
-			return fmt.Errorf("init dependencies: %w", err)
-		}
-	}
-
-	err = initModule(modulePath)
-	if err != nil {
-		return fmt.Errorf("init module: %w", err)
-	}
-	return nil
-}

internal/mod/probe_linux.go

@@ -0,0 +1,37 @@
+package mod
+
+import (
+	"fmt"
+)
+
+// Probe loads the given kernel module and its dependencies.
+func Probe(moduleName string) error {
+	modulesInfo, err := getModulesInfo()
+	if err != nil {
+		return fmt.Errorf("getting modules information: %w", err)
+	}
+
+	modulePath, err := findModulePath(moduleName, modulesInfo)
+	if err != nil {
+		return fmt.Errorf("finding module path: %w", err)
+	}
+
+	info := modulesInfo[modulePath]
+	if info.state == builtin || info.state == loaded {
+		return nil
+	}
+
+	info.state = loading
+	for _, dependencyModulePath := range info.dependencyPaths {
+		err = initDependencies(dependencyModulePath, modulesInfo)
+		if err != nil {
+			return fmt.Errorf("init dependencies: %w", err)
+		}
+	}
+
+	err = initModule(modulePath)
+	if err != nil {
+		return fmt.Errorf("init module: %w", err)
+	}
+	return nil
+}

internal/mod/probe_unspecified.go

@@ -0,0 +1,7 @@
+//go:build !linux
+
+package mod
+
+func Probe(moduleName string) error {
+	panic("not implemented")
+}

internal/netlink/address.go

@@ -1,33 +1,75 @@
-//go:build linux || darwin
-
 package netlink
 
 import (
-	"github.com/vishvananda/netlink"
+	"fmt"
+	"net"
+	"net/netip"
+
+	"github.com/jsimonetti/rtnetlink/rtnl"
 )
 
-func (n *NetLink) AddrList(link Link, family int) (
-	addresses []Addr, err error,
+func (n *NetLink) AddrList(linkIndex uint32, family uint8) (
+	ipPrefixes []netip.Prefix, err error,
 ) {
-	netlinkLink := linkToNetlinkLink(&link)
-	netlinkAddresses, err := netlink.AddrList(netlinkLink, family)
+	conn, err := rtnl.Dial(nil)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	ifc := &net.Interface{
+		Index: int(linkIndex),
+	}
+	ipNets, err := conn.Addrs(ifc, int(family))
+	if err != nil {
+		return nil, fmt.Errorf("failed to list addresses: %w", err)
 	}
 
-	addresses = make([]Addr, len(netlinkAddresses))
-	for i := range netlinkAddresses {
-		addresses[i].Network = netIPNetToNetipPrefix(netlinkAddresses[i].IPNet)
+	ipPrefixes = make([]netip.Prefix, len(ipNets))
+	for i := range ipNets {
+		ipPrefixes[i] = netIPNetToNetipPrefix(ipNets[i])
 	}
 
-	return addresses, nil
+	return ipPrefixes, nil
 }
 
-func (n *NetLink) AddrReplace(link Link, addr Addr) error {
-	netlinkLink := linkToNetlinkLink(&link)
-	netlinkAddress := netlink.Addr{
-		IPNet: netipPrefixToIPNet(addr.Network),
+func (n *NetLink) AddrReplace(linkIndex uint32, prefix netip.Prefix) error {
+	conn, err := rtnl.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	ipNet := netipPrefixToIPNet(prefix)
+
+	// Remove any address identical to the one we want to add
+	family := FamilyV4
+	if prefix.Addr().Is6() {
+		family = FamilyV6
+	}
+	ifc := &net.Interface{
+		Index: int(linkIndex),
+	}
+	addresses, err := conn.Addrs(ifc, int(family))
+	if err != nil {
+		return fmt.Errorf("listing addresses: %w", err)
+	}
+	for _, address := range addresses {
+		if address.IP.Equal(ipNet.IP) &&
+			net.IP(address.Mask).String() == net.IP(ipNet.Mask).String() {
+			err = conn.AddrDel(ifc, address)
+			if err != nil {
+				return fmt.Errorf("deleting address from interface: %w", err)
+			}
+			break
+		}
 	}
 
-	return netlink.AddrReplace(netlinkLink, &netlinkAddress)
+	// Add the new address to the interface
+	err = conn.AddrAdd(ifc, ipNet)
+	if err != nil {
+		return fmt.Errorf("adding address to interface: %w", err)
+	}
+
+	return nil
 }

internal/netlink/address_unspecified.go

@@ -1,13 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) AddrList(link Link, family int) (
-	addresses []Addr, err error,
-) {
-	panic("not implemented")
-}
-
-func (n *NetLink) AddrReplace(Link, Addr) error {
-	panic("not implemented")
-}

internal/netlink/conversion.go

@@ -36,6 +36,30 @@ func netIPNetToNetipPrefix(ipNet *net.IPNet) (prefix netip.Prefix) {
 	return netip.PrefixFrom(ip, bits)
 }
 
+func ipAndLengthToPrefix(ip *net.IP, length uint8) netip.Prefix {
+	if ip == nil || len(*ip) == 0 {
+		return netip.Prefix{}
+	}
+	var dstIP netip.Addr
+	if ipv4 := ip.To4(); ipv4 != nil { // IPv6
+		dstIP = netip.AddrFrom4([4]byte(*ip))
+	} else {
+		dstIP = netip.AddrFrom16([16]byte(*ip))
+	}
+	return netip.PrefixFrom(dstIP, int(length))
+}
+
+func prefixToIPAndLength(prefix netip.Prefix) (ip *net.IP, length uint8) {
+	if !prefix.IsValid() {
+		return nil, 0
+	}
+	prefixIP := prefix.Addr().Unmap()
+	ip = new(net.IP)
+	*ip = netipAddrToNetIP(prefixIP)
+	length = uint8(prefix.Bits()) //nolint:gosec
+	return ip, length
+}
+
 func netipAddrToNetIP(address netip.Addr) (ip net.IP) {
 	switch {
 	case !address.IsValid():

internal/netlink/family.go

@@ -4,13 +4,7 @@ import (
 	"fmt"
 )
 
-const (
-	FamilyAll = 0
-	FamilyV4  = 2
-	FamilyV6  = 10
-)
-
-func FamilyToString(family int) string {
+func FamilyToString(family uint8) string {
 	switch family {
 	case FamilyAll:
 		return "all"

internal/netlink/family_linux.go

@@ -0,0 +1,9 @@
+package netlink
+
+import "golang.org/x/sys/unix"
+
+const (
+	FamilyAll uint8 = unix.AF_UNSPEC
+	FamilyV4  uint8 = unix.AF_INET
+	FamilyV6  uint8 = unix.AF_INET6
+)

internal/netlink/helpers_test.go

@@ -1,16 +1,30 @@
 package netlink
 
 import (
+	"math/rand/v2"
 	"net/netip"
 
 	"github.com/qdm12/log"
 )
 
+func ptrTo[T any](v T) *T { return &v }
+
 func makeNetipPrefix(n byte) netip.Prefix {
 	const bits = 24
 	return netip.PrefixFrom(netip.AddrFrom4([4]byte{n, n, n, 0}), bits)
 }
 
+var rng = rand.New(rand.NewChaCha8([32]byte{})) //nolint:gosec,gochecknoglobals
+
+func makeLinkName() string {
+	const alphabet = "abcdefghijklmnopqrstuvwxyz"
+	name := make([]byte, 8)
+	for i := range name {
+		name[i] = alphabet[rng.IntN(len(alphabet))]
+	}
+	return "test" + string(name)
+}
+
 type noopLogger struct{}
 
 func (l *noopLogger) Debug(_ string)            {}

internal/netlink/ipv6.go

@@ -19,7 +19,7 @@ func (n *NetLink) IsIPv6Supported() (supported bool, err error) {
 			return false, fmt.Errorf("finding link corresponding to route: %w", err)
 		}
 
-		sourceIsIPv6 := route.Src.IsValid() && route.Src.Is6()
+		sourceIsIPv6 := route.Src.Addr().IsValid() && route.Src.Addr().Is6()
 		destinationIsIPv6 := route.Dst.IsValid() && route.Dst.Addr().Is6()
 		switch {
 		case !sourceIsIPv6 && !destinationIsIPv6,

internal/netlink/link.go

@@ -1,105 +1,191 @@
-//go:build linux || darwin
-
 package netlink
 
-import "github.com/vishvananda/netlink"
+import (
+	"errors"
+	"fmt"
+
+	"github.com/jsimonetti/rtnetlink"
+)
+
+type DeviceType uint16
+
+type Link struct {
+	Index       uint32
+	Name        string
+	DeviceType  DeviceType
+	VirtualType string
+	MTU         uint32
+}
 
 func (n *NetLink) LinkList() (links []Link, err error) {
-	netlinkLinks, err := netlink.LinkList()
+	conn, err := rtnetlink.Dial(nil)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	linkMessages, err := conn.Link.List()
+	if err != nil {
+		return nil, fmt.Errorf("listing interfaces: %w", err)
 	}
 
-	links = make([]Link, len(netlinkLinks))
-	for i := range netlinkLinks {
-		links[i] = netlinkLinkToLink(netlinkLinks[i])
+	links = make([]Link, len(linkMessages))
+	for i, message := range linkMessages {
+		virtualType := ""
+		if message.Attributes.Info != nil {
+			virtualType = message.Attributes.Info.Kind
+		}
+		links[i] = Link{
+			Index:       message.Index,
+			Name:        message.Attributes.Name,
+			DeviceType:  DeviceType(message.Type),
+			VirtualType: virtualType,
+			MTU:         message.Attributes.MTU,
+		}
 	}
 
 	return links, nil
 }
 
+var ErrLinkNotFound = errors.New("link not found")
+
 func (n *NetLink) LinkByName(name string) (link Link, err error) {
-	netlinkLink, err := netlink.LinkByName(name)
+	links, err := n.LinkList()
 	if err != nil {
-		return Link{}, err
+		return Link{}, fmt.Errorf("listing links: %w", err)
 	}
 
-	return netlinkLinkToLink(netlinkLink), nil
+	for _, link := range links {
+		if link.Name == name {
+			return link, nil
+		}
+	}
+
+	return Link{}, fmt.Errorf("%w: for name %s", ErrLinkNotFound, name)
 }
 
-func (n *NetLink) LinkByIndex(index int) (link Link, err error) {
-	netlinkLink, err := netlink.LinkByIndex(index)
+func (n *NetLink) LinkByIndex(index uint32) (link Link, err error) {
+	links, err := n.LinkList()
 	if err != nil {
-		return Link{}, err
+		return Link{}, fmt.Errorf("listing links: %w", err)
 	}
 
-	return netlinkLinkToLink(netlinkLink), nil
+	for _, link = range links {
+		if link.Index == index {
+			return link, nil
+		}
+	}
+
+	return Link{}, fmt.Errorf("%w: for index %d", ErrLinkNotFound, index)
 }
 
-func (n *NetLink) LinkAdd(link Link) (linkIndex int, err error) {
-	netlinkLink := linkToNetlinkLink(&link)
-	err = netlink.LinkAdd(netlinkLink)
+func (n *NetLink) LinkAdd(link Link) (linkIndex uint32, err error) {
+	conn, err := rtnetlink.Dial(nil)
 	if err != nil {
-		return 0, err
+		return 0, fmt.Errorf("dialing netlink: %w", err)
 	}
-	return netlinkLink.Attrs().Index, nil
-}
+	defer conn.Close()
 
-func (n *NetLink) LinkDel(link Link) (err error) {
-	return netlink.LinkDel(linkToNetlinkLink(&link))
-}
-
-func (n *NetLink) LinkSetUp(link Link) (linkIndex int, err error) {
-	netlinkLink := linkToNetlinkLink(&link)
-	err = netlink.LinkSetUp(netlinkLink)
-	if err != nil {
-		return 0, err
-	}
-	return netlinkLink.Attrs().Index, nil
-}
-
-func (n *NetLink) LinkSetDown(link Link) (err error) {
-	return netlink.LinkSetDown(linkToNetlinkLink(&link))
-}
-
-type netlinkLinkImpl struct {
-	attrs    *netlink.LinkAttrs
-	linkType string
-}
-
-func (n *netlinkLinkImpl) Attrs() *netlink.LinkAttrs {
-	return n.attrs
-}
-
-func (n *netlinkLinkImpl) Type() string {
-	return n.linkType
-}
-
-func netlinkLinkToLink(netlinkLink netlink.Link) Link {
-	attributes := netlinkLink.Attrs()
-	return Link{
-		Type:      netlinkLink.Type(),
-		Name:      attributes.Name,
-		Index:     attributes.Index,
-		EncapType: attributes.EncapType,
-		MTU:       uint16(attributes.MTU), //nolint:gosec
-	}
-}
-
-// Warning: we must return `netlink.Link` and not `netlinkLinkImpl`
-// so that the vishvananda/netlink package can compare the returned
-// value against an untyped nil.
-func linkToNetlinkLink(link *Link) netlink.Link {
-	if link == nil {
-		return nil
-	}
-	return &netlinkLinkImpl{
-		linkType: link.Type,
-		attrs: &netlink.LinkAttrs{
+	tx := &rtnetlink.LinkMessage{
+		Type: uint16(link.DeviceType),
+		Attributes: &rtnetlink.LinkAttributes{
+			MTU:  link.MTU,
 			Name: link.Name,
-			Index:     link.Index,
-			EncapType: link.EncapType,
-			MTU:       int(link.MTU),
 		},
 	}
+	if link.VirtualType != "" {
+		tx.Attributes.Info = &rtnetlink.LinkInfo{
+			Kind: link.VirtualType,
+		}
+	}
+
+	err = conn.Link.New(tx)
+	if err != nil {
+		return 0, fmt.Errorf("creating new link: %w", err)
+	}
+
+	linkMessages, err := conn.Link.List()
+	if err != nil {
+		return 0, fmt.Errorf("listing links: %w", err)
+	}
+	for _, linkMessage := range linkMessages {
+		if linkMessage.Attributes.Name == link.Name {
+			return linkMessage.Index, nil
+		}
+	}
+
+	return 0, fmt.Errorf("%w: matching name %s", ErrLinkNotFound, link.Name)
+}
+
+func (n *NetLink) LinkDel(linkIndex uint32) (err error) {
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	return conn.Link.Delete(linkIndex)
+}
+
+func (n *NetLink) LinkSetUp(linkIndex uint32) (err error) {
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	rx, err := conn.Link.Get(linkIndex)
+	if err != nil {
+		return fmt.Errorf("getting link: %w", err)
+	}
+	tx := &rtnetlink.LinkMessage{
+		Type:   rx.Type,
+		Index:  linkIndex,
+		Flags:  iffUp,
+		Change: iffUp,
+	}
+	return conn.Link.Set(tx)
+}
+
+func (n *NetLink) LinkSetDown(linkIndex uint32) (err error) {
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	linkInfo, err := conn.Link.Get(linkIndex)
+	if err != nil {
+		return fmt.Errorf("getting link: %w", err)
+	}
+	message := &rtnetlink.LinkMessage{
+		Type:   linkInfo.Type,
+		Index:  linkIndex,
+		Flags:  0,
+		Change: iffUp,
+	}
+	return conn.Link.Set(message)
+}
+
+func (n *NetLink) LinkSetMTU(linkIndex, mtu uint32) error {
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	message := &rtnetlink.LinkMessage{
+		Index: linkIndex,
+		Attributes: &rtnetlink.LinkAttributes{
+			MTU: mtu,
+		},
+	}
+
+	err = conn.Link.Set(message)
+	if err != nil {
+		return fmt.Errorf("setting MTU to %d for link at index %d: %w",
+			mtu, linkIndex, err)
+	}
+
+	return nil
 }

internal/netlink/link_linux.go

@@ -0,0 +1,11 @@
+package netlink
+
+import "golang.org/x/sys/unix"
+
+const (
+	DeviceTypeEthernet DeviceType = unix.ARPHRD_ETHER
+	DeviceTypeLoopback DeviceType = unix.ARPHRD_LOOPBACK
+	DeviceTypeNone     DeviceType = unix.ARPHRD_NONE
+
+	iffUp = unix.IFF_UP
+)

internal/netlink/link_test.go

@@ -0,0 +1,85 @@
+//go:build linux
+
+package netlink
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_NetLink_LinkList(t *testing.T) {
+	t.Parallel()
+
+	netlink := &NetLink{}
+
+	initialLinks, err := netlink.LinkList()
+	require.NoError(t, err)
+	require.NotEmpty(t, initialLinks)
+
+	loopbackFound := false
+	for _, link := range initialLinks {
+		if link.Name != "lo" {
+			continue
+		}
+		loopbackFound = true
+		assert.Equal(t, DeviceTypeLoopback, link.DeviceType)
+		break
+	}
+	assert.True(t, loopbackFound, "loopback interface not found")
+
+	testLink := Link{
+		Name: makeLinkName(),
+		// note if [Link.VirtualType] is set, [Link.DeviceType]
+		// is ignored and gets set to [DeviceTypeNone] in LinkAdd.
+		DeviceType:  DeviceTypeNone,
+		VirtualType: "wireguard",
+		MTU:         1420,
+	}
+	index, err := netlink.LinkAdd(testLink)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = netlink.LinkDel(index)
+	})
+
+	links, err := netlink.LinkList()
+	require.NoError(t, err)
+
+	testLink.Index = index
+	for _, link := range links {
+		if link.Name != testLink.Name {
+			continue
+		}
+		assert.Equal(t, testLink, link)
+		return
+	}
+	t.Errorf("created link %q not found", testLink.Name)
+}
+
+func Test_NetLink_LinkSetMTU(t *testing.T) {
+	t.Parallel()
+
+	netlink := &NetLink{}
+
+	testLink := Link{
+		Name:        makeLinkName(),
+		DeviceType:  DeviceTypeNone,
+		VirtualType: "wireguard",
+		MTU:         1420,
+	}
+	index, err := netlink.LinkAdd(testLink)
+	require.NoError(t, err)
+	t.Cleanup(func() {
+		_ = netlink.LinkDel(index)
+	})
+	testLink.Index = index
+
+	err = netlink.LinkSetMTU(index, 1500)
+	require.NoError(t, err)
+
+	link, err := netlink.LinkByIndex(index)
+	require.NoError(t, err)
+	testLink.MTU = 1500
+	assert.Equal(t, testLink, link)
+}

internal/netlink/link_unspecified.go

@@ -1,31 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) LinkList() (links []Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByName(name string) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkByIndex(index int) (link Link, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkAdd(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkDel(link Link) (err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetUp(link Link) (linkIndex int, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) LinkSetDown(link Link) (err error) {
-	panic("not implemented")
-}

internal/netlink/netlink_unspecified.go

@@ -0,0 +1,56 @@
+//go:build !linux
+
+package netlink
+
+const (
+	// FamilyAll is a placeholder only and should not
+	// be used.
+	FamilyAll uint8 = iota
+	// FamilyV4 is a placeholder only and should not
+	// be used.
+	FamilyV4
+	// FamilyV6 is a placeholder only and should not
+	// be used.
+	FamilyV6
+
+	// DeviceTypeEthernet is a placeholder only and should not be used.
+	DeviceTypeEthernet DeviceType = 0
+	// DeviceTypeLoopback is a placeholder only and should not be used.
+	DeviceTypeLoopback DeviceType = 0
+	// DeviceTypeNone is a placeholder only and should not be used.
+	DeviceTypeNone DeviceType = 0
+
+	// iffUp is a placeholder only and should not be used.
+	iffUp = 0
+
+	// RouteTypeUnicast is a placeholder only and should not be used.
+	RouteTypeUnicast = 0
+	// ScopeUniverse is a placeholder only and should not be used.
+	ScopeUniverse = 0
+	// ProtoStatic is a placeholder only and should not be used.
+	ProtoStatic = 0
+
+	// FlagInvert is a placeholder only and should not be used.
+	FlagInvert = 0
+	// ActionToTable is a placeholder only and should not be used.
+	ActionToTable = 0
+
+	// rtTableCompat is a placeholder only and should not be used.
+	rtTableCompat = 0
+)
+
+func (n *NetLink) RuleList(family uint8) (rules []Rule, err error) {
+	panic("not implemented")
+}
+
+func (n *NetLink) RuleAdd(rule Rule) error {
+	panic("not implemented")
+}
+
+func (n *NetLink) RuleDel(rule Rule) error {
+	panic("not implemented")
+}
+
+func (n *NetLink) IsWireguardSupported() (bool, error) {
+	panic("not implemented")
+}

internal/netlink/route.go

@@ -1,69 +1,125 @@
-//go:build linux || darwin
-
 package netlink
 
 import (
-	"github.com/vishvananda/netlink"
+	"fmt"
+	"net/netip"
+
+	"github.com/jsimonetti/rtnetlink"
 )
 
-func (n *NetLink) RouteList(family int) (routes []Route, err error) {
-	// We set the filter to netlink.RT_FILTER_TABLE so that
-	// routes from all tables are listed, as long as the filter
-	// table is set to 0.
-	const filterMask = netlink.RT_FILTER_TABLE
-	// The filter is not left to `nil` otherwise non-main tables
-	// are ignored.
-	filter := &netlink.Route{}
+type Route struct {
+	LinkIndex uint32
+	Dst       netip.Prefix
+	Src       netip.Prefix
+	Gw        netip.Addr
+	Priority  uint32
+	Family    uint8
+	Table     uint32
+	Type      uint8
+	Scope     uint8
+	Proto     uint8
+}
 
-	netlinkRoutes, err := netlink.RouteListFiltered(family, filter, filterMask)
+func (r *Route) fromMessage(message rtnetlink.RouteMessage) {
+	table := uint32(message.Table)
+	if table == 0 || table == rtTableCompat {
+		table = message.Attributes.Table
+	}
+	r.LinkIndex = message.Attributes.OutIface
+	r.Dst = ipAndLengthToPrefix(&message.Attributes.Dst, message.DstLength)
+	r.Src = ipAndLengthToPrefix(&message.Attributes.Src, message.SrcLength)
+	r.Gw = netIPToNetipAddress(message.Attributes.Gateway)
+	r.Priority = message.Attributes.Priority
+	r.Family = message.Family
+	r.Table = table
+	r.Type = message.Type
+	r.Scope = message.Scope
+	r.Proto = message.Protocol
+}
+
+func (r Route) message() *rtnetlink.RouteMessage {
+	dst, dstLength := prefixToIPAndLength(r.Dst)
+	src, srcLength := prefixToIPAndLength(r.Src)
+	var table uint8
+	var extendedTable uint32
+	if r.Table <= uint32(^uint8(0)) {
+		table = uint8(r.Table)
+	} else {
+		table = rtTableCompat
+		extendedTable = r.Table
+	}
+	message := &rtnetlink.RouteMessage{
+		Family:    r.Family,
+		DstLength: dstLength,
+		SrcLength: srcLength,
+		Table:     table,
+		Type:      r.Type,
+		Scope:     r.Scope,
+		Protocol:  r.Proto,
+		Attributes: rtnetlink.RouteAttributes{
+			OutIface: r.LinkIndex,
+			Dst:      *dst, // there should always be a dst for routes
+			Gateway:  netipAddrToNetIP(r.Gw),
+			Priority: r.Priority,
+			Table:    extendedTable,
+		},
+	}
+	if src != nil { // src is optional
+		message.Attributes.Src = *src
+	}
+	return message
+}
+
+func (n *NetLink) RouteList(family uint8) (routes []Route, err error) {
+	conn, err := rtnetlink.Dial(nil)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	routeMessages, err := conn.Route.List()
+	if err != nil {
+		return nil, fmt.Errorf("listing interfaces: %w", err)
 	}
 
-	routes = make([]Route, len(netlinkRoutes))
-	for i := range netlinkRoutes {
-		routes[i] = netlinkRouteToRoute(netlinkRoutes[i])
+	routes = make([]Route, 0, len(routeMessages))
+	for _, routeMessage := range routeMessages {
+		if family != FamilyAll && routeMessage.Family != family {
+			continue
+		}
+		var route Route
+		route.fromMessage(routeMessage)
+		routes = append(routes, route)
 	}
 	return routes, nil
 }
 
 func (n *NetLink) RouteAdd(route Route) error {
-	netlinkRoute := routeToNetlinkRoute(route)
-	return netlink.RouteAdd(&netlinkRoute)
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	return conn.Route.Add(route.message())
 }
 
 func (n *NetLink) RouteDel(route Route) error {
-	netlinkRoute := routeToNetlinkRoute(route)
-	return netlink.RouteDel(&netlinkRoute)
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	return conn.Route.Delete(route.message())
 }
 
 func (n *NetLink) RouteReplace(route Route) error {
-	netlinkRoute := routeToNetlinkRoute(route)
-	return netlink.RouteReplace(&netlinkRoute)
-}
-
-func netlinkRouteToRoute(netlinkRoute netlink.Route) (route Route) {
-	return Route{
-		LinkIndex: netlinkRoute.LinkIndex,
-		Dst:       netIPNetToNetipPrefix(netlinkRoute.Dst),
-		Src:       netIPToNetipAddress(netlinkRoute.Src),
-		Gw:        netIPToNetipAddress(netlinkRoute.Gw),
-		Priority:  netlinkRoute.Priority,
-		Family:    netlinkRoute.Family,
-		Table:     netlinkRoute.Table,
-		Type:      netlinkRoute.Type,
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
 	}
-}
+	defer conn.Close()
 
-func routeToNetlinkRoute(route Route) (netlinkRoute netlink.Route) {
-	return netlink.Route{
-		LinkIndex: route.LinkIndex,
-		Dst:       netipPrefixToIPNet(route.Dst),
-		Src:       netipAddrToNetIP(route.Src),
-		Gw:        netipAddrToNetIP(route.Gw),
-		Priority:  route.Priority,
-		Family:    route.Family,
-		Table:     route.Table,
-		Type:      route.Type,
-	}
+	return conn.Route.Replace(route.message())
 }

internal/netlink/route_linux.go

@@ -0,0 +1,11 @@
+package netlink
+
+import "golang.org/x/sys/unix"
+
+const (
+	RouteTypeUnicast = unix.RTN_UNICAST
+	ScopeUniverse    = unix.RT_SCOPE_UNIVERSE
+	ProtoStatic      = unix.RTPROT_STATIC
+
+	rtTableCompat = unix.RT_TABLE_COMPAT
+)

internal/netlink/route_unspecified.go

@@ -1,21 +0,0 @@
-//go:build !linux && !darwin
-
-package netlink
-
-func (n *NetLink) RouteList(family int) (
-	routes []Route, err error,
-) {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteAdd(route Route) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteDel(route Route) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RouteReplace(route Route) error {
-	panic("not implemented")
-}

internal/netlink/rule.go

@@ -1,91 +1,96 @@
-//go:build linux
-
 package netlink
 
 import (
 	"fmt"
+	"net/netip"
 
-	"github.com/vishvananda/netlink"
+	"github.com/jsimonetti/rtnetlink"
 )
 
-func NewRule() Rule {
-	// defaults found from netlink.NewRule() for fields we use,
-	// the rest of the defaults is set when converting from a `Rule`
-	// to a `netlink.Rule`
-	return Rule{
-		Priority: -1,
-		Mark:     0,
-	}
+type Rule struct {
+	Priority *uint32
+	Family   uint8
+	Table    uint32
+	Mark     *uint32
+	Src      netip.Prefix
+	Dst      netip.Prefix
+	Flags    uint32
+	Action   uint8
 }
 
-func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
-	switch family {
-	case FamilyAll:
-		n.debugLogger.Debug("ip -4 rule list")
-		n.debugLogger.Debug("ip -6 rule list")
-	case FamilyV4:
-		n.debugLogger.Debug("ip -4 rule list")
-	case FamilyV6:
-		n.debugLogger.Debug("ip -6 rule list")
+func (r *Rule) fromMessage(message rtnetlink.RuleMessage) {
+	table := uint32(message.Table)
+	if table == 0 || table == rtTableCompat {
+		table = *message.Attributes.Table
 	}
-	netlinkRules, err := netlink.RuleList(family)
-	if err != nil {
-		return nil, err
+	r.Priority = message.Attributes.Priority
+	r.Family = message.Family
+	r.Table = table
+	r.Mark = message.Attributes.FwMark
+	r.Src = ipAndLengthToPrefix(message.Attributes.Src, message.SrcLength)
+	r.Dst = ipAndLengthToPrefix(message.Attributes.Dst, message.DstLength)
+	r.Flags = message.Flags
+	r.Action = message.Action
+}
+
+func (r Rule) message() *rtnetlink.RuleMessage {
+	src, srcLength := prefixToIPAndLength(r.Src)
+	dst, dstLength := prefixToIPAndLength(r.Dst)
+
+	message := &rtnetlink.RuleMessage{
+		Family:    r.Family,
+		SrcLength: srcLength,
+		DstLength: dstLength,
+		Flags:     r.Flags,
+		Action:    r.Action,
+		Attributes: &rtnetlink.RuleAttributes{
+			Priority: r.Priority,
+			FwMark:   r.Mark,
+			Src:      src,
+			Dst:      dst,
+		},
 	}
 
-	rules = make([]Rule, len(netlinkRules))
-	for i := range netlinkRules {
-		rules[i] = netlinkRuleToRule(netlinkRules[i])
+	if r.Table <= uint32(^uint8(0)) {
+		message.Table = uint8(r.Table)
+	} else {
+		message.Table = rtTableCompat
+		message.Attributes.Table = &r.Table
 	}
-	return rules, nil
+
+	return message
 }
 
-func (n *NetLink) RuleAdd(rule Rule) error {
-	n.debugLogger.Debug(ruleDbgMsg(true, rule))
-	netlinkRule := ruleToNetlinkRule(rule)
-	return netlink.RuleAdd(&netlinkRule)
-}
-
-func (n *NetLink) RuleDel(rule Rule) error {
-	n.debugLogger.Debug(ruleDbgMsg(false, rule))
-	netlinkRule := ruleToNetlinkRule(rule)
-	return netlink.RuleDel(&netlinkRule)
-}
-
-func ruleToNetlinkRule(rule Rule) (netlinkRule netlink.Rule) {
-	netlinkRule = *netlink.NewRule()
-	netlinkRule.Priority = rule.Priority
-	netlinkRule.Family = rule.Family
-	netlinkRule.Table = rule.Table
-	netlinkRule.Mark = rule.Mark
-	netlinkRule.Src = netipPrefixToIPNet(rule.Src)
-	netlinkRule.Dst = netipPrefixToIPNet(rule.Dst)
-	netlinkRule.Invert = rule.Invert
-	return netlinkRule
-}
-
-func netlinkRuleToRule(netlinkRule netlink.Rule) (rule Rule) {
-	return Rule{
-		Priority: netlinkRule.Priority,
-		Family:   netlinkRule.Family,
-		Table:    netlinkRule.Table,
-		Mark:     netlinkRule.Mark,
-		Src:      netIPNetToNetipPrefix(netlinkRule.Src),
-		Dst:      netIPNetToNetipPrefix(netlinkRule.Dst),
-		Invert:   netlinkRule.Invert,
+func (r Rule) String() string {
+	from := "all"
+	if r.Src.IsValid() && !r.Src.Addr().IsUnspecified() {
+		from = r.Src.String()
 	}
+
+	to := "all"
+	if r.Dst.IsValid() && !r.Dst.Addr().IsUnspecified() {
+		to = r.Dst.String()
+	}
+
+	priority := ""
+	if r.Priority != nil {
+		priority = fmt.Sprintf(" %d", *r.Priority)
+	}
+
+	return fmt.Sprintf("ip rule%s: from %s to %s table %d",
+		priority, from, to, r.Table)
 }
 
-func ruleDbgMsg(add bool, rule Rule) (debugMessage string) {
+func (r Rule) debugMessage(add bool) (debugMessage string) {
 	debugMessage = "ip"
 
-	switch rule.Family {
+	switch r.Family {
 	case FamilyV4:
 		debugMessage += " -f inet"
 	case FamilyV6:
 		debugMessage += " -f inet6"
 	default:
-		debugMessage += " -f " + fmt.Sprint(rule.Family)
+		debugMessage += " -f " + fmt.Sprint(r.Family)
 	}
 
 	debugMessage += " rule"
@@ -96,20 +101,20 @@ func ruleDbgMsg(add bool, rule Rule) (debugMessage string) {
 		debugMessage += " del"
 	}
 
-	if rule.Src.IsValid() {
-		debugMessage += " from " + rule.Src.String()
+	if r.Src.IsValid() {
+		debugMessage += " from " + r.Src.String()
 	}
 
-	if rule.Dst.IsValid() {
-		debugMessage += " to " + rule.Dst.String()
+	if r.Dst.IsValid() {
+		debugMessage += " to " + r.Dst.String()
 	}
 
-	if rule.Table != 0 {
-		debugMessage += " lookup " + fmt.Sprint(rule.Table)
+	if r.Table != 0 {
+		debugMessage += " lookup " + fmt.Sprint(r.Table)
 	}
 
-	if rule.Priority != -1 {
-		debugMessage += " pref " + fmt.Sprint(rule.Priority)
+	if r.Priority != nil {
+		debugMessage += " pref " + fmt.Sprint(*r.Priority)
 	}
 
 	return debugMessage

internal/netlink/rule_linux.go

@@ -0,0 +1,69 @@
+package netlink
+
+import (
+	"fmt"
+
+	"github.com/jsimonetti/rtnetlink"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	FlagInvert    = unix.FIB_RULE_INVERT
+	ActionToTable = unix.FR_ACT_TO_TBL
+)
+
+func (n *NetLink) RuleList(family uint8) (rules []Rule, err error) {
+	switch family {
+	case FamilyAll:
+		n.debugLogger.Debug("ip -4 rule list")
+		n.debugLogger.Debug("ip -6 rule list")
+	case FamilyV4:
+		n.debugLogger.Debug("ip -4 rule list")
+	case FamilyV6:
+		n.debugLogger.Debug("ip -6 rule list")
+	}
+
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return nil, fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	ruleMessages, err := conn.Rule.List()
+	if err != nil {
+		return nil, err
+	}
+
+	rules = make([]Rule, 0, len(ruleMessages))
+	for _, message := range ruleMessages {
+		if family != FamilyAll && family != message.Family {
+			continue
+		}
+		var rule Rule
+		rule.fromMessage(message)
+		rules = append(rules, rule)
+	}
+	return rules, nil
+}
+
+func (n *NetLink) RuleAdd(rule Rule) error {
+	n.debugLogger.Debug(rule.debugMessage(true))
+
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+	return conn.Rule.Add(rule.message())
+}
+
+func (n *NetLink) RuleDel(rule Rule) error {
+	n.debugLogger.Debug(rule.debugMessage(false))
+
+	conn, err := rtnetlink.Dial(nil)
+	if err != nil {
+		return fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+	return conn.Rule.Delete(rule.message())
+}

internal/netlink/rule_test.go

@@ -6,7 +6,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func Test_ruleDbgMsg(t *testing.T) {
+func Test_Rule_debugMessage(t *testing.T) {
 	t.Parallel()
 
 	testCases := map[string]struct {
@@ -15,7 +15,7 @@ func Test_ruleDbgMsg(t *testing.T) {
 		dbgMsg string
 	}{
 		"default values": {
-			dbgMsg: "ip -f 0 rule del pref 0",
+			dbgMsg: "ip -f 0 rule del",
 		},
 		"add rule": {
 			add: true,
@@ -24,7 +24,7 @@ func Test_ruleDbgMsg(t *testing.T) {
 				Src:      makeNetipPrefix(1),
 				Dst:      makeNetipPrefix(2),
 				Table:    100,
-				Priority: 101,
+				Priority: ptrTo(uint32(101)),
 			},
 			dbgMsg: "ip -f inet rule add from 1.1.1.0/24 to 2.2.2.0/24 lookup 100 pref 101",
 		},
@@ -34,7 +34,7 @@ func Test_ruleDbgMsg(t *testing.T) {
 				Src:      makeNetipPrefix(1),
 				Dst:      makeNetipPrefix(2),
 				Table:    100,
-				Priority: 101,
+				Priority: ptrTo(uint32(101)),
 			},
 			dbgMsg: "ip -f inet rule del from 1.1.1.0/24 to 2.2.2.0/24 lookup 100 pref 101",
 		},
@@ -44,7 +44,7 @@ func Test_ruleDbgMsg(t *testing.T) {
 		t.Run(name, func(t *testing.T) {
 			t.Parallel()
 
-			dbgMsg := ruleDbgMsg(testCase.add, testCase.rule)
+			dbgMsg := testCase.rule.debugMessage(testCase.add)
 
 			assert.Equal(t, testCase.dbgMsg, dbgMsg)
 		})

internal/netlink/rule_unspecified.go

@@ -1,19 +0,0 @@
-//go:build !linux
-
-package netlink
-
-func NewRule() Rule {
-	return Rule{}
-}
-
-func (n *NetLink) RuleList(family int) (rules []Rule, err error) {
-	panic("not implemented")
-}
-
-func (n *NetLink) RuleAdd(rule Rule) error {
-	panic("not implemented")
-}
-
-func (n *NetLink) RuleDel(rule Rule) error {
-	panic("not implemented")
-}

internal/netlink/types.go

@@ -1,58 +0,0 @@
-package netlink
-
-import (
-	"fmt"
-	"net/netip"
-)
-
-type Addr struct {
-	Network netip.Prefix
-}
-
-func (a Addr) String() string {
-	return a.Network.String()
-}
-
-type Link struct {
-	Type      string
-	Name      string
-	Index     int
-	EncapType string
-	MTU       uint16
-}
-
-type Route struct {
-	LinkIndex int
-	Dst       netip.Prefix
-	Src       netip.Addr
-	Gw        netip.Addr
-	Priority  int
-	Family    int
-	Table     int
-	Type      int
-}
-
-type Rule struct {
-	Priority int
-	Family   int
-	Table    int
-	Mark     uint32
-	Src      netip.Prefix
-	Dst      netip.Prefix
-	Invert   bool
-}
-
-func (r Rule) String() string {
-	from := "all"
-	if r.Src.IsValid() && !r.Src.Addr().IsUnspecified() {
-		from = r.Src.String()
-	}
-
-	to := "all"
-	if r.Dst.IsValid() && !r.Dst.Addr().IsUnspecified() {
-		to = r.Dst.String()
-	}
-
-	return fmt.Sprintf("ip rule %d: from %s to %s table %d",
-		r.Priority, from, to, r.Table)
-}

internal/netlink/wireguard.go

@@ -1,37 +0,0 @@
-//go:build linux
-
-package netlink
-
-import (
-	"github.com/qdm12/gluetun/internal/mod"
-	"github.com/vishvananda/netlink"
-)
-
-func (n *NetLink) IsWireguardSupported() bool {
-	// Check for Wireguard family without loading the wireguard module.
-	// Some kernels have the wireguard module built-in, and don't have a
-	// modules directory, such as WSL2 kernels.
-	ok := hasWireguardFamily()
-	if ok {
-		return true
-	}
-
-	// Try loading the wireguard module, since some systems do not load
-	// it after a boot. If this fails, wireguard is assumed to not be supported.
-	n.debugLogger.Debugf("wireguard family not found, trying to load wireguard kernel module")
-	err := mod.Probe("wireguard")
-	if err != nil {
-		n.debugLogger.Debugf("failed loading wireguard kernel module: %s", err)
-		return false
-	}
-	n.debugLogger.Debugf("wireguard kernel module loaded successfully")
-
-	// Re-check if the Wireguard family is now available, after loading
-	// the wireguard kernel module.
-	return hasWireguardFamily()
-}
-
-func hasWireguardFamily() bool {
-	_, err := netlink.GenlFamilyGet("wireguard")
-	return err == nil
-}

internal/netlink/wireguard_linux.go

@@ -0,0 +1,58 @@
+package netlink
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/mdlayher/genetlink"
+	"github.com/qdm12/gluetun/internal/mod"
+)
+
+func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
+	// Check for Wireguard family without loading the wireguard module.
+	// Some kernels have the wireguard module built-in, and don't have a
+	// modules directory, such as WSL2 kernels.
+	ok, err = hasWireguardFamily()
+	if err != nil {
+		return false, fmt.Errorf("checking wireguard family: %w", err)
+	} else if ok {
+		return true, nil
+	}
+
+	// Try loading the wireguard module, since some systems do not load
+	// it after a boot. If this fails, wireguard is assumed to not be supported.
+	n.debugLogger.Debugf("wireguard family not found, trying to load wireguard kernel module")
+	err = mod.Probe("wireguard")
+	if err != nil {
+		n.debugLogger.Debugf("failed loading wireguard kernel module: %s", err)
+		return false, nil
+	}
+	n.debugLogger.Debugf("wireguard kernel module loaded successfully")
+
+	// Re-check if the Wireguard family is now available, after loading
+	// the wireguard kernel module.
+	ok, err = hasWireguardFamily()
+	if err != nil {
+		return false, fmt.Errorf("checking wireguard family: %w", err)
+	}
+	return ok, nil
+}
+
+func hasWireguardFamily() (ok bool, err error) {
+	conn, err := genetlink.Dial(nil)
+	if err != nil {
+		return false, fmt.Errorf("dialing netlink: %w", err)
+	}
+	defer conn.Close()
+
+	_, err = conn.GetFamily("wireguard")
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return false, nil
+		}
+		return false, fmt.Errorf("getting wireguard family: %w", err)
+	}
+
+	return true, nil
+}

internal/netlink/wireguard_test.go

@@ -4,6 +4,8 @@ package netlink
 
 import (
 	"testing"
+
+	"github.com/stretchr/testify/require"
 )
 
 func Test_NetLink_IsWireguardSupported(t *testing.T) {
@@ -12,7 +14,8 @@ func Test_NetLink_IsWireguardSupported(t *testing.T) {
 	netLink := &NetLink{
 		debugLogger: &noopLogger{},
 	}
-	ok := netLink.IsWireguardSupported()
+	ok, err := netLink.IsWireguardSupported()
+	require.NoError(t, err)
 	if ok { // cannot assert since this depends on kernel
 		t.Log("wireguard is supported")
 	} else {

internal/netlink/wireguard_unspecified.go

@@ -1,7 +0,0 @@
-//go:build !linux
-
-package netlink
-
-func (n *NetLink) IsWireguardSupported() (ok bool, err error) {
-	panic("not implemented")
-}

internal/openvpn/extract/extract.go

@@ -55,8 +55,6 @@ func extractDataFromLines(lines []string) (
 func extractDataFromLine(line string) (
 	ip netip.Addr, port uint16, protocol string, err error,
 ) {
-	line = strings.TrimSpace(line)
-
 	switch {
 	case strings.HasPrefix(line, "proto "):
 		protocol, err = extractProto(line)
@@ -83,7 +81,10 @@ func extractDataFromLine(line string) (
 	return ip, 0, "", nil
 }
 
-var errProtoLineFieldsCount = errors.New("proto line has not 2 fields as expected")
+var (
+	errProtoLineFieldsCount = errors.New("proto line has not 2 fields as expected")
+	errProtocolNotSupported = errors.New("network protocol not supported")
+)
 
 func extractProto(line string) (protocol string, err error) {
 	fields := strings.Fields(line)
@@ -91,25 +92,13 @@ func extractProto(line string) (protocol string, err error) {
 		return "", fmt.Errorf("%w: %s", errProtoLineFieldsCount, line)
 	}
 
-	return parseProto(fields[1])
-}
-
-var errProtocolNotSupported = errors.New("network protocol not supported")
-
-func parseProto(field string) (protocol string, err error) {
-	switch field {
-	case "tcp", "tcp4", "tcp6", "tcp-client":
-		// tcp4, tcp6 can be assimilated as tcp since the IP version is
-		// determined by the remote IP address version.
-		// tcp-client is a synonym of tcp for OpenVPN 2.5+ acting in client mode.
-		return constants.TCP, nil
-	case "udp", "udp4", "udp6":
-		// udp4, udp6 can be assimilated as udp since the IP version is
-		// determined by the remote IP address version.
-		return constants.UDP, nil
+	switch fields[1] {
+	case "tcp", "tcp4", "tcp6", "tcp-client", "udp", "udp4", "udp6":
 	default:
-		return "", fmt.Errorf("%w: %s", errProtocolNotSupported, field)
+		return "", fmt.Errorf("%w: %s", errProtocolNotSupported, fields[1])
 	}
+
+	return fields[1], nil
 }
 
 var (
@@ -147,9 +136,11 @@ func extractRemote(line string) (ip netip.Addr, port uint16,
 	}
 
 	if n > 3 { //nolint:mnd
-		protocol, err = parseProto(fields[3])
-		if err != nil {
-			return netip.Addr{}, 0, "", fmt.Errorf("parsing protocol from remote line: %w", err)
+		switch fields[3] {
+		case "tcp", "udp":
+			protocol = fields[3]
+		default:
+			return netip.Addr{}, 0, "", fmt.Errorf("%w: %s", errProtocolNotSupported, fields[3])
 		}
 	}
 

internal/openvpn/extract/extract_test.go

@@ -62,14 +62,6 @@ func Test_extractDataFromLines(t *testing.T) {
 				Protocol: constants.UDP,
 			},
 		},
-		"leading_whitespace": {
-			lines: []string{"  proto tcp", "\tremote 1.2.3.4 443 tcp"},
-			connection: models.Connection{
-				IP:       netip.AddrFrom4([4]byte{1, 2, 3, 4}),
-				Port:     443,
-				Protocol: constants.TCP,
-			},
-		},
 	}
 
 	for name, testCase := range testCases {
@@ -113,7 +105,7 @@ func Test_extractDataFromLine(t *testing.T) {
 		},
 		"tcp-client": {
 			line:     "proto tcp-client",
-			protocol: constants.TCP,
+			protocol: "tcp-client",
 		},
 		"extract remote error": {
 			line:  "remote bad",
@@ -247,7 +239,7 @@ func Test_extractRemote(t *testing.T) {
 		},
 		"invalid protocol": {
 			line: "remote 1.2.3.4 8000 bad",
-			err:  errors.New("parsing protocol from remote line: network protocol not supported: bad"),
+			err:  errors.New("network protocol not supported: bad"),
 		},
 		"IP host and port and protocol": {
 			line:     "remote 1.2.3.4 8000 udp",

internal/openvpn/run.go

@@ -29,16 +29,19 @@ func (r *Runner) Run(ctx context.Context, errCh chan<- error, ready chan<- struc
 		return
 	}
 
+	streamCtx, streamCancel := context.WithCancel(context.Background())
 	streamDone := make(chan struct{})
-	go streamLines(streamDone, r.logger,
+	go streamLines(streamCtx, streamDone, r.logger,
 		stdoutLines, stderrLines, ready)
 
 	select {
 	case <-ctx.Done():
 		<-waitError
+		streamCancel()
 		<-streamDone
 		errCh <- ctx.Err()
 	case err := <-waitError:
+		streamCancel()
 		<-streamDone
 		errCh <- err
 	}

internal/openvpn/start.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"os/exec"
-	"syscall"
 
 	"github.com/qdm12/gluetun/internal/constants/openvpn"
 )
@@ -33,7 +32,7 @@ func start(ctx context.Context, starter CmdStarter, version string, flags []stri
 	args := []string{"--config", configPath}
 	args = append(args, flags...)
 	cmd := exec.CommandContext(ctx, bin, args...)
-	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	setCmdSysProcAttr(cmd)
 
 	return starter.Start(cmd)
 }

internal/openvpn/start_linux.go

@@ -0,0 +1,10 @@
+package openvpn
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func setCmdSysProcAttr(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+}

internal/openvpn/start_unspecified.go

@@ -0,0 +1,12 @@
+//go:build !linux
+
+package openvpn
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func setCmdSysProcAttr(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{}
+}

internal/openvpn/stream.go

@@ -1,37 +1,26 @@
 package openvpn
 
 import (
+	"context"
 	"strings"
 )
 
-func streamLines(done chan<- struct{},
+func streamLines(ctx context.Context, done chan<- struct{},
 	logger Logger, stdout, stderr <-chan string,
 	tunnelReady chan<- struct{},
 ) {
 	defer close(done)
 
-	for {
 	var line string
-		var ok bool
+
+	for {
 		errLine := false
 		select {
-		case line, ok = <-stdout:
-			if ok {
-				break
-			}
-			if stderr == nil {
+		case <-ctx.Done():
 			return
-			}
-			stdout = nil
-		case line, ok = <-stderr:
-			if ok {
+		case line = <-stdout:
+		case line = <-stderr:
 			errLine = true
-				break
-			}
-			if stdout == nil {
-				return
-			}
-			stderr = nil
 		}
 		line, level := processLogLine(line)
 		if line == "" {

internal/pmtud/apple_ipv4.go

@@ -0,0 +1,49 @@
+package pmtud
+
+import (
+	"net"
+	"time"
+
+	"golang.org/x/net/ipv4"
+)
+
+var _ net.PacketConn = &ipv4Wrapper{}
+
+// ipv4Wrapper is a wrapper around ipv4.PacketConn to implement
+// the net.PacketConn interface. It's only used for Darwin or iOS.
+type ipv4Wrapper struct {
+	ipv4Conn *ipv4.PacketConn
+}
+
+func ipv4ToNetPacketConn(ipv4 *ipv4.PacketConn) *ipv4Wrapper {
+	return &ipv4Wrapper{ipv4Conn: ipv4}
+}
+
+func (i *ipv4Wrapper) ReadFrom(p []byte) (n int, addr net.Addr, err error) {
+	n, _, addr, err = i.ipv4Conn.ReadFrom(p)
+	return n, addr, err
+}
+
+func (i *ipv4Wrapper) WriteTo(p []byte, addr net.Addr) (n int, err error) {
+	return i.ipv4Conn.WriteTo(p, nil, addr)
+}
+
+func (i *ipv4Wrapper) Close() error {
+	return i.ipv4Conn.Close()
+}
+
+func (i *ipv4Wrapper) LocalAddr() net.Addr {
+	return i.ipv4Conn.LocalAddr()
+}
+
+func (i *ipv4Wrapper) SetDeadline(t time.Time) error {
+	return i.ipv4Conn.SetDeadline(t)
+}
+
+func (i *ipv4Wrapper) SetReadDeadline(t time.Time) error {
+	return i.ipv4Conn.SetReadDeadline(t)
+}
+
+func (i *ipv4Wrapper) SetWriteDeadline(t time.Time) error {
+	return i.ipv4Conn.SetWriteDeadline(t)
+}

internal/pmtud/check.go

@@ -0,0 +1,83 @@
+package pmtud
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+
+	"golang.org/x/net/icmp"
+)
+
+var (
+	ErrICMPNextHopMTUTooLow  = errors.New("ICMP Next Hop MTU is too low")
+	ErrICMPNextHopMTUTooHigh = errors.New("ICMP Next Hop MTU is too high")
+)
+
+func checkMTU(mtu, minMTU, physicalLinkMTU uint32) (err error) {
+	switch {
+	case mtu < minMTU:
+		return fmt.Errorf("%w: %d", ErrICMPNextHopMTUTooLow, mtu)
+	case mtu > physicalLinkMTU:
+		return fmt.Errorf("%w: %d is larger than physical link MTU %d",
+			ErrICMPNextHopMTUTooHigh, mtu, physicalLinkMTU)
+	default:
+		return nil
+	}
+}
+
+func checkInvokingReplyIDMatch(icmpProtocol int, received []byte,
+	outboundMessage *icmp.Message,
+) (match bool, err error) {
+	inboundMessage, err := icmp.ParseMessage(icmpProtocol, received)
+	if err != nil {
+		return false, fmt.Errorf("parsing invoking packet: %w", err)
+	}
+	inboundBody, ok := inboundMessage.Body.(*icmp.Echo)
+	if !ok {
+		return false, fmt.Errorf("%w: %T", ErrICMPBodyUnsupported, inboundMessage.Body)
+	}
+	outboundBody := outboundMessage.Body.(*icmp.Echo) //nolint:forcetypeassert
+	return inboundBody.ID == outboundBody.ID, nil
+}
+
+var ErrICMPIDMismatch = errors.New("ICMP id mismatch")
+
+func checkEchoReply(icmpProtocol int, received []byte,
+	outboundMessage *icmp.Message, truncatedBody bool,
+) (err error) {
+	inboundMessage, err := icmp.ParseMessage(icmpProtocol, received)
+	if err != nil {
+		return fmt.Errorf("parsing invoking packet: %w", err)
+	}
+	inboundBody, ok := inboundMessage.Body.(*icmp.Echo)
+	if !ok {
+		return fmt.Errorf("%w: %T", ErrICMPBodyUnsupported, inboundMessage.Body)
+	}
+	outboundBody := outboundMessage.Body.(*icmp.Echo) //nolint:forcetypeassert
+	if inboundBody.ID != outboundBody.ID {
+		return fmt.Errorf("%w: sent id %d and received id %d",
+			ErrICMPIDMismatch, outboundBody.ID, inboundBody.ID)
+	}
+	err = checkEchoBodies(outboundBody.Data, inboundBody.Data, truncatedBody)
+	if err != nil {
+		return fmt.Errorf("checking sent and received bodies: %w", err)
+	}
+	return nil
+}
+
+var ErrICMPEchoDataMismatch = errors.New("ICMP data mismatch")
+
+func checkEchoBodies(sent, received []byte, receivedTruncated bool) (err error) {
+	if len(received) > len(sent) {
+		return fmt.Errorf("%w: sent %d bytes and received %d bytes",
+			ErrICMPEchoDataMismatch, len(sent), len(received))
+	}
+	if receivedTruncated {
+		sent = sent[:len(received)]
+	}
+	if !bytes.Equal(received, sent) {
+		return fmt.Errorf("%w: sent %x and received %x",
+			ErrICMPEchoDataMismatch, sent, received)
+	}
+	return nil
+}

internal/pmtud/df.go

@@ -0,0 +1,10 @@
+//go:build !linux && !windows
+
+package pmtud
+
+// setDontFragment for platforms other than Linux and Windows
+// is not implemented, so we just return assuming the don't
+// fragment flag is set on IP packets.
+func setDontFragment(fd uintptr) (err error) {
+	return nil
+}

internal/pmtud/df_linux.go

@@ -0,0 +1,10 @@
+package pmtud
+
+import (
+	"syscall"
+)
+
+func setDontFragment(fd uintptr) (err error) {
+	return syscall.SetsockoptInt(int(fd), syscall.IPPROTO_IP,
+		syscall.IP_MTU_DISCOVER, syscall.IP_PMTUDISC_PROBE)
+}

internal/pmtud/df_windows.go

@@ -0,0 +1,13 @@
+//go:build windows
+
+package pmtud
+
+import (
+	"syscall"
+)
+
+func setDontFragment(fd uintptr) (err error) {
+	// https://docs.microsoft.com/en-us/troubleshoot/windows/win32/header-library-requirement-socket-ipproto-ip
+	// #define IP_DONTFRAGMENT        14     /* don't fragment IP datagrams */
+	return syscall.SetsockoptInt(syscall.Handle(fd), syscall.IPPROTO_IP, 14, 1)
+}

internal/pmtud/errors.go

@@ -0,0 +1,29 @@
+package pmtud
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+	"time"
+)
+
+var (
+	ErrICMPNotPermitted                            = errors.New("ICMP not permitted")
+	ErrICMPDestinationUnreachable                  = errors.New("ICMP destination unreachable")
+	ErrICMPCommunicationAdministrativelyProhibited = errors.New("communication administratively prohibited")
+	ErrICMPBodyUnsupported                         = errors.New("ICMP body type is not supported")
+)
+
+func wrapConnErr(err error, timedCtx context.Context, pingTimeout time.Duration) error { //nolint:revive
+	switch {
+	case strings.HasSuffix(err.Error(), "sendto: operation not permitted"):
+		err = fmt.Errorf("%w", ErrICMPNotPermitted)
+	case errors.Is(timedCtx.Err(), context.DeadlineExceeded):
+		err = fmt.Errorf("%w (timed out after %s)", net.ErrClosed, pingTimeout)
+	case timedCtx.Err() != nil:
+		err = timedCtx.Err()
+	}
+	return err
+}

internal/pmtud/interfaces.go

@@ -0,0 +1,7 @@
+package pmtud
+
+type Logger interface {
+	Debug(msg string)
+	Debugf(msg string, args ...any)
+	Warnf(msg string, args ...any)
+}

internal/pmtud/ipv4.go

@@ -0,0 +1,159 @@
+package pmtud
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"net"
+	"net/netip"
+	"runtime"
+	"strings"
+	"syscall"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+)
+
+const (
+	// see https://en.wikipedia.org/wiki/Maximum_transmission_unit#MTUs_for_common_media
+	minIPv4MTU     uint32 = 68
+	icmpv4Protocol int    = 1
+)
+
+func listenICMPv4(ctx context.Context) (conn net.PacketConn, err error) {
+	var listenConfig net.ListenConfig
+	listenConfig.Control = func(_, _ string, rawConn syscall.RawConn) error {
+		var setDFErr error
+		err := rawConn.Control(func(fd uintptr) {
+			setDFErr = setDontFragment(fd) // runs when calling ListenPacket
+		})
+		if err == nil {
+			err = setDFErr
+		}
+		return err
+	}
+
+	const listenAddress = ""
+	packetConn, err := listenConfig.ListenPacket(ctx, "ip4:icmp", listenAddress)
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "socket: operation not permitted") {
+			err = fmt.Errorf("%w: you can try adding NET_RAW capability to resolve this", ErrICMPNotPermitted)
+		}
+		return nil, err
+	}
+
+	if runtime.GOOS == "darwin" || runtime.GOOS == "ios" {
+		packetConn = ipv4ToNetPacketConn(ipv4.NewPacketConn(packetConn))
+	}
+
+	return packetConn, nil
+}
+
+func findIPv4NextHopMTU(ctx context.Context, ip netip.Addr,
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger,
+) (mtu uint32, err error) {
+	if ip.Is6() {
+		panic("IP address is not v4")
+	}
+	conn, err := listenICMPv4(ctx)
+	if err != nil {
+		return 0, fmt.Errorf("listening for ICMP packets: %w", err)
+	}
+	ctx, cancel := context.WithTimeout(ctx, pingTimeout)
+	defer cancel()
+	go func() {
+		<-ctx.Done()
+		conn.Close()
+	}()
+
+	// First try to send a packet which is too big to get the maximum MTU
+	// directly.
+	outboundID, outboundMessage := buildMessageToSend("v4", physicalLinkMTU)
+	encodedMessage, err := outboundMessage.Marshal(nil)
+	if err != nil {
+		return 0, fmt.Errorf("encoding ICMP message: %w", err)
+	}
+
+	_, err = conn.WriteTo(encodedMessage, &net.IPAddr{IP: ip.AsSlice()})
+	if err != nil {
+		err = wrapConnErr(err, ctx, pingTimeout)
+		return 0, fmt.Errorf("writing ICMP message: %w", err)
+	}
+
+	buffer := make([]byte, physicalLinkMTU)
+
+	for { // for loop in case we read an echo reply for another ICMP request
+		// Note we need to read the whole packet in one call to ReadFrom, so the buffer
+		// must be large enough to read the entire reply packet. See:
+		// https://groups.google.com/g/golang-nuts/c/5dy2Q4nPs08/m/KmuSQAGEtG4J
+		bytesRead, _, err := conn.ReadFrom(buffer)
+		if err != nil {
+			err = wrapConnErr(err, ctx, pingTimeout)
+			return 0, fmt.Errorf("reading from ICMP connection: %w", err)
+		}
+		packetBytes := buffer[:bytesRead]
+		// Side note: echo reply should be at most the number of bytes
+		// sent, and can be lower, more precisely 576-ipHeader bytes,
+		// in case the next hop we are reaching replies with a destination
+		// unreachable and wants to ensure the response makes it way back
+		// by keeping a low packet size, see:
+		// https://datatracker.ietf.org/doc/html/rfc1122#page-59
+
+		inboundMessage, err := icmp.ParseMessage(icmpv4Protocol, packetBytes)
+		if err != nil {
+			return 0, fmt.Errorf("parsing message: %w", err)
+		}
+
+		switch typedBody := inboundMessage.Body.(type) {
+		case *icmp.DstUnreach:
+			const fragmentationRequiredAndDFFlagSetCode = 4
+			const communicationAdministrativelyProhibitedCode = 13
+			switch inboundMessage.Code {
+			case fragmentationRequiredAndDFFlagSetCode:
+			case communicationAdministrativelyProhibitedCode:
+				return 0, fmt.Errorf("%w: %w (code %d)",
+					ErrICMPDestinationUnreachable,
+					ErrICMPCommunicationAdministrativelyProhibited,
+					inboundMessage.Code)
+			default:
+				return 0, fmt.Errorf("%w: code %d",
+					ErrICMPDestinationUnreachable, inboundMessage.Code)
+			}
+
+			// See https://datatracker.ietf.org/doc/html/rfc1191#section-4
+			// Note: the go library does not handle this NextHopMTU section.
+			nextHopMTU := packetBytes[6:8]
+			mtu = uint32(binary.BigEndian.Uint16(nextHopMTU))
+			err = checkMTU(mtu, minIPv4MTU, physicalLinkMTU)
+			if err != nil {
+				return 0, fmt.Errorf("checking next-hop-mtu found: %w", err)
+			}
+
+			// The code below is really for sanity checks
+			packetBytes = packetBytes[8:]
+			header, err := ipv4.ParseHeader(packetBytes)
+			if err != nil {
+				return 0, fmt.Errorf("parsing IPv4 header: %w", err)
+			}
+			packetBytes = packetBytes[header.Len:] // truncated original datagram
+
+			const truncated = true
+			err = checkEchoReply(icmpv4Protocol, packetBytes, outboundMessage, truncated)
+			if err != nil {
+				return 0, fmt.Errorf("checking echo reply: %w", err)
+			}
+			return mtu, nil
+		case *icmp.Echo:
+			inboundID := uint16(typedBody.ID) //nolint:gosec
+			if inboundID == outboundID {
+				return physicalLinkMTU, nil
+			}
+			logger.Debugf("discarding received ICMP echo reply with id %d mismatching sent id %d",
+				inboundID, outboundID)
+			continue
+		default:
+			return 0, fmt.Errorf("%w: %T", ErrICMPBodyUnsupported, typedBody)
+		}
+	}
+}

internal/pmtud/ipv6.go

@@ -0,0 +1,122 @@
+package pmtud
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/netip"
+	"strings"
+	"time"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv6"
+)
+
+const (
+	minIPv6MTU     = 1280
+	icmpv6Protocol = 58
+)
+
+func listenICMPv6(ctx context.Context) (conn net.PacketConn, err error) {
+	var listenConfig net.ListenConfig
+	const listenAddress = ""
+	packetConn, err := listenConfig.ListenPacket(ctx, "ip6:ipv6-icmp", listenAddress)
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "socket: operation not permitted") {
+			err = fmt.Errorf("%w: you can try adding NET_RAW capability to resolve this", ErrICMPNotPermitted)
+		}
+		return nil, err
+	}
+	return packetConn, nil
+}
+
+func getIPv6PacketTooBig(ctx context.Context, ip netip.Addr,
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger,
+) (mtu uint32, err error) {
+	if ip.Is4() {
+		panic("IP address is not v6")
+	}
+	conn, err := listenICMPv6(ctx)
+	if err != nil {
+		return 0, fmt.Errorf("listening for ICMP packets: %w", err)
+	}
+	ctx, cancel := context.WithTimeout(ctx, pingTimeout)
+	defer cancel()
+	go func() {
+		<-ctx.Done()
+		conn.Close()
+	}()
+
+	// First try to send a packet which is too big to get the maximum MTU
+	// directly.
+	outboundID, outboundMessage := buildMessageToSend("v6", physicalLinkMTU)
+	encodedMessage, err := outboundMessage.Marshal(nil)
+	if err != nil {
+		return 0, fmt.Errorf("encoding ICMP message: %w", err)
+	}
+
+	_, err = conn.WriteTo(encodedMessage, &net.IPAddr{IP: ip.AsSlice(), Zone: ip.Zone()})
+	if err != nil {
+		err = wrapConnErr(err, ctx, pingTimeout)
+		return 0, fmt.Errorf("writing ICMP message: %w", err)
+	}
+
+	buffer := make([]byte, physicalLinkMTU)
+
+	for { // for loop if we encounter another ICMP packet with an unknown id.
+		// Note we need to read the whole packet in one call to ReadFrom, so the buffer
+		// must be large enough to read the entire reply packet. See:
+		// https://groups.google.com/g/golang-nuts/c/5dy2Q4nPs08/m/KmuSQAGEtG4J
+		bytesRead, _, err := conn.ReadFrom(buffer)
+		if err != nil {
+			err = wrapConnErr(err, ctx, pingTimeout)
+			return 0, fmt.Errorf("reading from ICMP connection: %w", err)
+		}
+		packetBytes := buffer[:bytesRead]
+
+		packetBytes = packetBytes[ipv6.HeaderLen:]
+
+		inboundMessage, err := icmp.ParseMessage(icmpv6Protocol, packetBytes)
+		if err != nil {
+			return 0, fmt.Errorf("parsing message: %w", err)
+		}
+
+		switch typedBody := inboundMessage.Body.(type) {
+		case *icmp.PacketTooBig:
+			// https://datatracker.ietf.org/doc/html/rfc1885#section-3.2
+			mtu = uint32(typedBody.MTU) //nolint:gosec
+			err = checkMTU(mtu, minIPv6MTU, physicalLinkMTU)
+			if err != nil {
+				return 0, fmt.Errorf("checking MTU: %w", err)
+			}
+
+			// Sanity checks
+			const truncatedBody = true
+			err = checkEchoReply(icmpv6Protocol, typedBody.Data, outboundMessage, truncatedBody)
+			if err != nil {
+				return 0, fmt.Errorf("checking invoking message: %w", err)
+			}
+			return uint32(typedBody.MTU), nil //nolint:gosec
+		case *icmp.DstUnreach:
+			// https://datatracker.ietf.org/doc/html/rfc1885#section-3.1
+			idMatch, err := checkInvokingReplyIDMatch(icmpv6Protocol, packetBytes, outboundMessage)
+			if err != nil {
+				return 0, fmt.Errorf("checking invoking message id: %w", err)
+			} else if idMatch {
+				return 0, fmt.Errorf("%w", ErrICMPDestinationUnreachable)
+			}
+			logger.Debug("discarding received ICMP destination unreachable reply with an unknown id")
+			continue
+		case *icmp.Echo:
+			inboundID := uint16(typedBody.ID) //nolint:gosec
+			if inboundID == outboundID {
+				return physicalLinkMTU, nil
+			}
+			logger.Debugf("discarding received ICMP echo reply with id %d mismatching sent id %d",
+				inboundID, outboundID)
+			continue
+		default:
+			return 0, fmt.Errorf("%w: %T", ErrICMPBodyUnsupported, typedBody)
+		}
+	}
+}

internal/pmtud/message.go

@@ -0,0 +1,58 @@
+package pmtud
+
+import (
+	cryptorand "crypto/rand"
+	"encoding/binary"
+	"fmt"
+	"math/rand/v2"
+
+	"golang.org/x/net/icmp"
+	"golang.org/x/net/ipv4"
+	"golang.org/x/net/ipv6"
+)
+
+func buildMessageToSend(ipVersion string, mtu uint32) (id uint16, message *icmp.Message) {
+	var seed [32]byte
+	_, _ = cryptorand.Read(seed[:])
+	randomSource := rand.NewChaCha8(seed)
+
+	const uint16Bytes = 2
+	idBytes := make([]byte, uint16Bytes)
+	_, _ = randomSource.Read(idBytes)
+	id = binary.BigEndian.Uint16(idBytes)
+
+	var ipHeaderLength uint32
+	var icmpType icmp.Type
+	switch ipVersion {
+	case "v4":
+		ipHeaderLength = ipv4.HeaderLen
+		icmpType = ipv4.ICMPTypeEcho
+	case "v6":
+		ipHeaderLength = ipv6.HeaderLen
+		icmpType = ipv6.ICMPTypeEchoRequest
+	default:
+		panic(fmt.Sprintf("IP version %q not supported", ipVersion))
+	}
+	const pingHeaderLength = 0 +
+		1 + // type
+		1 + // code
+		2 + // checksum
+		2 + // identifier
+		2 // sequence number
+	pingBodyDataSize := mtu - ipHeaderLength - pingHeaderLength
+	messageBodyData := make([]byte, pingBodyDataSize)
+	_, _ = randomSource.Read(messageBodyData)
+
+	// See https://www.iana.org/assignments/icmp-parameters/icmp-parameters.xhtml#icmp-parameters-types
+	message = &icmp.Message{
+		Type:     icmpType, // echo request
+		Code:     0,        // no code
+		Checksum: 0,        // calculated at encoding (ipv4) or sending (ipv6)
+		Body: &icmp.Echo{
+			ID:   int(id),
+			Seq:  0, // only one packet
+			Data: messageBodyData,
+		},
+	}
+	return id, message
+}

internal/pmtud/nooplogger.go

@@ -0,0 +1,7 @@
+package pmtud
+
+type noopLogger struct{}
+
+func (noopLogger) Debug(_ string)            {}
+func (noopLogger) Debugf(_ string, _ ...any) {}
+func (noopLogger) Warnf(_ string, _ ...any)  {}

internal/pmtud/pmtud.go

@@ -0,0 +1,271 @@
+package pmtud
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"net"
+	"net/netip"
+	"strings"
+	"time"
+
+	"golang.org/x/net/icmp"
+)
+
+var ErrMTUNotFound = errors.New("path MTU discovery failed to find MTU")
+
+// PathMTUDiscover discovers the maximum MTU for the path to the given ip address.
+// If the physicalLinkMTU is zero, it defaults to 1500 which is the ethernet standard MTU.
+// If the pingTimeout is zero, it defaults to 1 second.
+// If the logger is nil, a no-op logger is used.
+// It returns [ErrMTUNotFound] if the MTU could not be determined.
+func PathMTUDiscover(ctx context.Context, ip netip.Addr,
+	physicalLinkMTU uint32, pingTimeout time.Duration, logger Logger) (
+	mtu uint32, err error,
+) {
+	if physicalLinkMTU == 0 {
+		const ethernetStandardMTU = 1500
+		physicalLinkMTU = ethernetStandardMTU
+	}
+	if pingTimeout == 0 {
+		pingTimeout = time.Second
+	}
+	if logger == nil {
+		logger = &noopLogger{}
+	}
+
+	if ip.Is4() {
+		logger.Debug("finding IPv4 next hop MTU")
+		mtu, err = findIPv4NextHopMTU(ctx, ip, physicalLinkMTU, pingTimeout, logger)
+		switch {
+		case err == nil:
+			return mtu, nil
+		case errors.Is(err, net.ErrClosed) || errors.Is(err, ErrICMPCommunicationAdministrativelyProhibited): // blackhole
+		default:
+			return 0, fmt.Errorf("finding IPv4 next hop MTU: %w", err)
+		}
+	} else {
+		logger.Debug("requesting IPv6 ICMP packet-too-big reply")
+		mtu, err = getIPv6PacketTooBig(ctx, ip, physicalLinkMTU, pingTimeout, logger)
+		switch {
+		case err == nil:
+			return mtu, nil
+		case errors.Is(err, net.ErrClosed): // blackhole
+		default:
+			return 0, fmt.Errorf("getting IPv6 packet-too-big message: %w", err)
+		}
+	}
+
+	// Fall back method: send echo requests with different packet
+	// sizes and check which ones succeed to find the maximum MTU.
+	logger.Debug("falling back to sending different sized echo packets")
+	minMTU := minIPv4MTU
+	if ip.Is6() {
+		minMTU = minIPv6MTU
+	}
+	return pmtudMultiSizes(ctx, ip, minMTU, physicalLinkMTU, pingTimeout, logger)
+}
+
+type pmtudTestUnit struct {
+	mtu       uint32
+	echoID    uint16
+	sentBytes int
+	ok        bool
+}
+
+func pmtudMultiSizes(ctx context.Context, ip netip.Addr,
+	minMTU, maxPossibleMTU uint32, pingTimeout time.Duration,
+	logger Logger,
+) (maxMTU uint32, err error) {
+	var ipVersion string
+	var conn net.PacketConn
+	if ip.Is4() {
+		ipVersion = "v4"
+		conn, err = listenICMPv4(ctx)
+	} else {
+		ipVersion = "v6"
+		conn, err = listenICMPv6(ctx)
+	}
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "socket: operation not permitted") {
+			err = fmt.Errorf("%w: you can try adding NET_RAW capability to resolve this", ErrICMPNotPermitted)
+		}
+		return 0, fmt.Errorf("listening for ICMP packets: %w", err)
+	}
+
+	mtusToTest := makeMTUsToTest(minMTU, maxPossibleMTU)
+	if len(mtusToTest) == 1 { // only minMTU because minMTU == maxPossibleMTU
+		return minMTU, nil
+	}
+	logger.Debugf("testing the following MTUs: %v", mtusToTest)
+
+	tests := make([]pmtudTestUnit, len(mtusToTest))
+	for i := range mtusToTest {
+		tests[i] = pmtudTestUnit{mtu: mtusToTest[i]}
+	}
+
+	timedCtx, cancel := context.WithTimeout(ctx, pingTimeout)
+	defer cancel()
+	go func() {
+		<-timedCtx.Done()
+		conn.Close()
+	}()
+
+	for i := range tests {
+		id, message := buildMessageToSend(ipVersion, tests[i].mtu)
+		tests[i].echoID = id
+
+		encodedMessage, err := message.Marshal(nil)
+		if err != nil {
+			return 0, fmt.Errorf("encoding ICMP message: %w", err)
+		}
+		tests[i].sentBytes = len(encodedMessage)
+
+		_, err = conn.WriteTo(encodedMessage, &net.IPAddr{IP: ip.AsSlice()})
+		if err != nil {
+			if strings.HasSuffix(err.Error(), "sendto: operation not permitted") {
+				err = fmt.Errorf("%w", ErrICMPNotPermitted)
+			}
+			return 0, fmt.Errorf("writing ICMP message: %w", err)
+		}
+	}
+
+	err = collectReplies(conn, ipVersion, tests, logger)
+	switch {
+	case err == nil: // max possible MTU is working
+		return tests[len(tests)-1].mtu, nil
+	case err != nil && errors.Is(err, net.ErrClosed):
+		// we have timeouts (IPv4 testing or IPv6 PMTUD blackholes)
+		// so find the highest MTU which worked.
+		// Note we start from index len(tests) - 2 since the max MTU
+		// cannot be working if we had a timeout.
+		for i := len(tests) - 2; i >= 0; i-- { //nolint:mnd
+			if tests[i].ok {
+				return pmtudMultiSizes(ctx, ip, tests[i].mtu, tests[i+1].mtu-1,
+					pingTimeout, logger)
+			}
+		}
+
+		// All MTUs failed.
+		return 0, fmt.Errorf("%w: ICMP might be blocked", ErrMTUNotFound)
+	case err != nil:
+		return 0, fmt.Errorf("collecting ICMP echo replies: %w", err)
+	default:
+		panic("unreachable")
+	}
+}
+
+// Create the MTU slice of length 11 such that:
+// - the first element is the minMTU
+// - the last element is the maxMTU
+// - elements in-between are separated as close to each other
+// The number 11 is chosen to find the final MTU in 3 searches,
+// with a total search space of 1728 MTUs which is enough;
+// to find it in 2 searches requires 37 parallel queries which
+// could be blocked by firewalls.
+func makeMTUsToTest(minMTU, maxMTU uint32) (mtus []uint32) {
+	const mtusLength = 11 // find the final MTU in 3 searches
+	diff := maxMTU - minMTU
+	switch {
+	case minMTU > maxMTU:
+		panic("minMTU > maxMTU")
+	case diff <= mtusLength:
+		mtus = make([]uint32, 0, diff)
+		for mtu := minMTU; mtu <= maxMTU; mtu++ {
+			mtus = append(mtus, mtu)
+		}
+	default:
+		step := float64(diff) / float64(mtusLength-1)
+		mtus = make([]uint32, 0, mtusLength)
+		for mtu := float64(minMTU); len(mtus) < mtusLength-1; mtu += step {
+			mtus = append(mtus, uint32(math.Round(mtu)))
+		}
+		mtus = append(mtus, maxMTU) // last element is the maxMTU
+	}
+
+	return mtus
+}
+
+func collectReplies(conn net.PacketConn, ipVersion string,
+	tests []pmtudTestUnit, logger Logger,
+) (err error) {
+	echoIDToTestIndex := make(map[uint16]int, len(tests))
+	for i, test := range tests {
+		echoIDToTestIndex[test.echoID] = i
+	}
+
+	// The theoretical limit is 4GiB for IPv6 MTU path discovery jumbograms, but that would
+	// create huge buffers which we don't really want to support anyway.
+	// The standard frame maximum MTU is 1500 bytes, and there are Jumbo frames with
+	// a conventional maximum of 9000 bytes. However, some manufacturers support up
+	// 9216-20 = 9196 bytes for the maximum MTU. We thus use buffers of size 9196 to
+	// match eventual Jumbo frames. More information at:
+	// https://en.wikipedia.org/wiki/Maximum_transmission_unit#MTUs_for_common_media
+	const maxPossibleMTU = 9196
+	buffer := make([]byte, maxPossibleMTU)
+
+	idsFound := 0
+	for idsFound < len(tests) {
+		// Note we need to read the whole packet in one call to ReadFrom, so the buffer
+		// must be large enough to read the entire reply packet. See:
+		// https://groups.google.com/g/golang-nuts/c/5dy2Q4nPs08/m/KmuSQAGEtG4J
+		bytesRead, _, err := conn.ReadFrom(buffer)
+		if err != nil {
+			return fmt.Errorf("reading from ICMP connection: %w", err)
+		}
+		packetBytes := buffer[:bytesRead]
+
+		ipPacketLength := len(packetBytes)
+
+		var icmpProtocol int
+		switch ipVersion {
+		case "v4":
+			icmpProtocol = icmpv4Protocol
+		case "v6":
+			icmpProtocol = icmpv6Protocol
+		default:
+			panic(fmt.Sprintf("unknown IP version: %s", ipVersion))
+		}
+
+		// Parse the ICMP message
+		// Note: this parsing works for a truncated 556 bytes ICMP reply packet.
+		message, err := icmp.ParseMessage(icmpProtocol, packetBytes)
+		if err != nil {
+			return fmt.Errorf("parsing message: %w", err)
+		}
+
+		echoBody, ok := message.Body.(*icmp.Echo)
+		if !ok {
+			return fmt.Errorf("%w: %T", ErrICMPBodyUnsupported, message.Body)
+		}
+
+		id := uint16(echoBody.ID) //nolint:gosec
+		testIndex, testing := echoIDToTestIndex[id]
+		if !testing { // not an id we expected so ignore it
+			logger.Warnf("ignoring ICMP reply with unexpected ID %d (type: %d, code: %d, length: %d)",
+				echoBody.ID, message.Type, message.Code, ipPacketLength)
+			continue
+		}
+		idsFound++
+		sentBytes := tests[testIndex].sentBytes
+
+		// echo reply should be at most the number of bytes sent,
+		// and can be lower, more precisely 556 bytes, in case
+		// the host we are reaching wants to stay out of trouble
+		// and ensure its echo reply goes through without
+		// fragmentation, see the following page:
+		// https://datatracker.ietf.org/doc/html/rfc1122#page-59
+		const conservativeReplyLength = 556
+		truncated := ipPacketLength < sentBytes &&
+			ipPacketLength == conservativeReplyLength
+		// Check the packet size is the same if the reply is not truncated
+		if !truncated && sentBytes != ipPacketLength {
+			return fmt.Errorf("%w: sent %dB and received %dB",
+				ErrICMPEchoDataMismatch, sentBytes, ipPacketLength)
+		}
+		// Truncated reply or matching reply size
+		tests[testIndex].ok = true
+	}
+	return nil
+}

internal/pmtud/pmtud_integration_test.go

@@ -0,0 +1,22 @@
+//go:build integration
+
+package pmtud
+
+import (
+	"context"
+	"net/netip"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_PathMTUDiscover(t *testing.T) {
+	t.Parallel()
+	const physicalLinkMTU = 1500
+	const timeout = time.Second
+	mtu, err := PathMTUDiscover(context.Background(), netip.MustParseAddr("1.1.1.1"),
+		physicalLinkMTU, timeout, nil)
+	require.NoError(t, err)
+	t.Log("MTU found:", mtu)
+}

internal/pmtud/pmtud_test.go

@@ -0,0 +1,55 @@
+package pmtud
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_makeMTUsToTest(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		minMTU uint32
+		maxMTU uint32
+		mtus   []uint32
+	}{
+		"0_0": {
+			mtus: []uint32{0},
+		},
+		"0_1": {
+			maxMTU: 1,
+			mtus:   []uint32{0, 1},
+		},
+		"0_8": {
+			maxMTU: 8,
+			mtus:   []uint32{0, 1, 2, 3, 4, 5, 6, 7, 8},
+		},
+		"0_12": {
+			maxMTU: 12,
+			mtus:   []uint32{0, 1, 2, 4, 5, 6, 7, 8, 10, 11, 12},
+		},
+		"0_80": {
+			maxMTU: 80,
+			mtus:   []uint32{0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80},
+		},
+		"0_100": {
+			maxMTU: 100,
+			mtus:   []uint32{0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100},
+		},
+		"1280_1500": {
+			minMTU: 1280,
+			maxMTU: 1500,
+			mtus:   []uint32{1280, 1302, 1324, 1346, 1368, 1390, 1412, 1434, 1456, 1478, 1500},
+		},
+	}
+
+	for name, testCase := range testCases {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			mtus := makeMTUsToTest(testCase.minMTU, testCase.maxMTU)
+			assert.Equal(t, testCase.mtus, mtus)
+		})
+	}
+}

internal/portforward/interfaces.go

@@ -14,7 +14,7 @@ type Service interface {
 
 type Routing interface {
 	VPNLocalGatewayIP(vpnInterface string) (gateway netip.Addr, err error)
-	AssignedIP(interfaceName string, family int) (ip netip.Addr, err error)
+	AssignedIP(interfaceName string, family uint8) (ip netip.Addr, err error)
 }
 
 type PortAllower interface {
@@ -29,7 +29,6 @@ type Logger interface {
 	Info(s string)
 	Warn(s string)
 	Error(s string)
-	Errorf(format string, args ...any)
 }
 
 type Cmder interface {

internal/portforward/loop.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net/http"
 	"sync"
-	"time"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/portforward/service"
@@ -86,8 +85,6 @@ func (l *Loop) run(runCtx context.Context, runDone chan<- struct{},
 	defer close(runDone)
 
 	var serviceRunError <-chan error
-	var retryAfter <-chan time.Time
-	const retryDelay = 5 * time.Second
 	for {
 		updateReceived := false
 		select {
@@ -106,12 +103,10 @@ func (l *Loop) run(runCtx context.Context, runDone chan<- struct{},
 			l.settingsMutex.Unlock()
 		case err := <-serviceRunError:
 			l.logger.Error(err.Error())
-		case <-retryAfter:
-			// Retry starting the service after a delay
-			retryAfter = nil
 		}
 
-		if l.service != nil {
+		firstRun := serviceRunError == nil
+		if !firstRun {
 			err := l.service.Stop()
 			if err != nil {
 				runErrorCh <- fmt.Errorf("stopping previous service: %w", err)
@@ -135,10 +130,6 @@ func (l *Loop) run(runCtx context.Context, runDone chan<- struct{},
 				err = fmt.Errorf("starting port forwarding service: %w", err)
 			}
 			updateResult <- err
-		} else if err != nil {
-			// Log the error and schedule a retry
-			l.logger.Errorf("starting port forwarding service: %s - retrying in %s", err, retryDelay)
-			retryAfter = time.After(retryDelay)
 		}
 	}
 }

internal/portforward/service/command.go

@@ -18,11 +18,7 @@ func runCommand(ctx context.Context, cmder Cmder, logger Logger,
 	}
 	portsString := strings.Join(portStrings, ",")
 	commandString := strings.ReplaceAll(commandTemplate, "{{PORTS}}", portsString)
-	var firstPort string
-	if len(portStrings) > 0 {
-		firstPort = portStrings[0]
-	}
-	commandString = strings.ReplaceAll(commandString, "{{PORT}}", firstPort)
+	commandString = strings.ReplaceAll(commandString, "{{PORT}}", portStrings[0])
 	commandString = strings.ReplaceAll(commandString, "{{VPN_INTERFACE}}", vpnInterface)
 	args, err := command.Split(commandString)
 	if err != nil {
@@ -35,39 +31,31 @@ func runCommand(ctx context.Context, cmder Cmder, logger Logger,
 		return err
 	}
 
+	streamCtx, streamCancel := context.WithCancel(context.Background())
 	streamDone := make(chan struct{})
-	go streamLines(streamDone, logger, stdout, stderr)
+	go streamLines(streamCtx, streamDone, logger, stdout, stderr)
 
 	err = <-waitError
+	streamCancel()
 	<-streamDone
 	return err
 }
 
-func streamLines(done chan<- struct{}, logger Logger,
-	stdout, stderr <-chan string,
+func streamLines(ctx context.Context, done chan<- struct{},
+	logger Logger, stdout, stderr <-chan string,
 ) {
 	defer close(done)
 
+	var line string
+
 	for {
 		select {
-		case line, ok := <-stdout:
-			if ok {
+		case <-ctx.Done():
+			return
+		case line = <-stdout:
 			logger.Info(line)
-				break
-			}
-			if stderr == nil {
-				return
-			}
-			stdout = nil
-		case line, ok := <-stderr:
-			if ok {
+		case line = <-stderr:
 			logger.Error(line)
-				break
-			}
-			if stdout == nil {
-				return
-			}
-			stderr = nil
 		}
 	}
 }

internal/portforward/service/interfaces.go

@@ -17,7 +17,7 @@ type PortAllower interface {
 
 type Routing interface {
 	VPNLocalGatewayIP(vpnInterface string) (gateway netip.Addr, err error)
-	AssignedIP(interfaceName string, family int) (ip netip.Addr, err error)
+	AssignedIP(interfaceName string, family uint8) (ip netip.Addr, err error)
 }
 
 type Logger interface {

internal/provider/custom/openvpnconf.go

@@ -7,7 +7,6 @@ import (
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
-	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/constants/openvpn"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
@@ -69,11 +68,7 @@ func modifyConfig(lines []string, connection models.Connection,
 	}
 
 	// Add values
-	protocol := connection.Protocol
-	if protocol == constants.TCP {
-		protocol = "tcp-client"
-	}
-	modified = append(modified, "proto "+protocol)
+	modified = append(modified, "proto "+connection.Protocol)
 	modified = append(modified, fmt.Sprintf("remote %s %d", connection.IP, connection.Port))
 	modified = append(modified, "dev "+settings.Interface)
 	modified = append(modified, "mute-replay-warnings")

internal/provider/expressvpn/openvpnconf.go

@@ -18,10 +18,7 @@ func (p *Provider) OpenVPNConfig(connection models.Connection,
 			openvpn.AES256gcm, openvpn.AES256cbc, openvpn.AES128gcm,
 		},
 		Auth:           openvpn.SHA512,
-		CAs: []string{
-			"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", //nolint:lll
-			"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",                                                                                                                                                                                                                                             //nolint:lll
-		},
+		CAs:            []string{"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"}, //nolint:lll
 		Cert:           "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",                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       //nolint:lll
 		RSAKey:         "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",                                                                                                                                                                                                                                                                                                                                                                                                                                                                               //nolint:lll
 		TLSAuth:        "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",                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       //nolint:lll

internal/provider/expressvpn/updater/hardcoded.go

@@ -108,6 +108,7 @@ func hardcodedServers() (servers []models.Server) {
 		{Country: "New Zealand", Hostname: "newzealand-ca-version-2.expressnetw.com"},
 		{Country: "North Macedonia", Hostname: "macedonia-ca-version-2.expressnetw.com"},
 		{Country: "Norway", Hostname: "norway-ca-version-2.expressnetw.com"},
+		{Country: "Pakistan", Hostname: "pakistan-ca-version-2.expressnetw.com"},
 		{Country: "Panama", Hostname: "panama-ca-version-2.expressnetw.com"},
 		{Country: "Peru", Hostname: "peru-ca-version-2.expressnetw.com"},
 		{Country: "Philippines (via Singapore)", Hostname: "ph-via-sing-ca-version-2.expressnetw.com"},

internal/provider/privado/connection.go

@@ -9,7 +9,7 @@ import (
 func (p *Provider) GetConnection(selection settings.ServerSelection, ipv6Supported bool) (
 	connection models.Connection, err error,
 ) {
-	defaults := utils.NewConnectionDefaults(1194, 1194, 0) //nolint:mnd
+	defaults := utils.NewConnectionDefaults(0, 1194, 0) //nolint:mnd
 	return utils.GetConnection(p.Name(),
 		p.storage, selection, defaults, ipv6Supported, p.randSource)
 }

internal/provider/privado/provider.go

@@ -2,7 +2,6 @@ package privado
 
 import (
 	"math/rand"
-	"net/http"
 
 	"github.com/qdm12/gluetun/internal/constants/providers"
 	"github.com/qdm12/gluetun/internal/provider/common"
@@ -16,12 +15,14 @@ type Provider struct {
 }
 
 func New(storage common.Storage, randSource rand.Source,
-	client *http.Client, updaterWarner common.Warner,
+	ipFetcher common.IPFetcher, unzipper common.Unzipper,
+	updaterWarner common.Warner,
+	parallelResolver common.ParallelResolver,
 ) *Provider {
 	return &Provider{
 		storage:    storage,
 		randSource: randSource,
-		Fetcher:    updater.New(client, updaterWarner),
+		Fetcher:    updater.New(ipFetcher, unzipper, updaterWarner, parallelResolver),
 	}
 }
 

internal/provider/privado/updater/hosttoserver.go

@@ -0,0 +1,50 @@
+package updater
+
+import (
+	"net/netip"
+
+	"github.com/qdm12/gluetun/internal/constants/vpn"
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+type hostToServer map[string]models.Server
+
+func (hts hostToServer) add(host string) {
+	server, ok := hts[host]
+	if ok {
+		return
+	}
+	server.VPN = vpn.OpenVPN
+	server.Hostname = host
+	server.UDP = true
+	hts[host] = server
+}
+
+func (hts hostToServer) toHostsSlice() (hosts []string) {
+	hosts = make([]string, 0, len(hts))
+	for host := range hts {
+		hosts = append(hosts, host)
+	}
+	return hosts
+}
+
+func (hts hostToServer) adaptWithIPs(hostToIPs map[string][]netip.Addr) {
+	for host, IPs := range hostToIPs {
+		server := hts[host]
+		server.IPs = IPs
+		hts[host] = server
+	}
+	for host, server := range hts {
+		if len(server.IPs) == 0 {
+			delete(hts, host)
+		}
+	}
+}
+
+func (hts hostToServer) toServersSlice() (servers []models.Server) {
+	servers = make([]models.Server, 0, len(hts))
+	for _, server := range hts {
+		servers = append(servers, server)
+	}
+	return servers
+}

internal/provider/privado/updater/location.go

@@ -0,0 +1,31 @@
+package updater
+
+import (
+	"context"
+	"net/netip"
+
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/provider/common"
+	"github.com/qdm12/gluetun/internal/publicip/api"
+)
+
+func setLocationInfo(ctx context.Context, fetcher common.IPFetcher, servers []models.Server) (err error) {
+	// Get public IP address information
+	ipsToGetInfo := make([]netip.Addr, 0, len(servers))
+	for _, server := range servers {
+		ipsToGetInfo = append(ipsToGetInfo, server.IPs...)
+	}
+	ipsInfo, err := api.FetchMultiInfo(ctx, fetcher, ipsToGetInfo)
+	if err != nil {
+		return err
+	}
+
+	for i := range servers {
+		ipInfo := ipsInfo[i]
+		servers[i].Country = ipInfo.Country
+		servers[i].Region = ipInfo.Region
+		servers[i].City = ipInfo.City
+	}
+
+	return nil
+}

internal/provider/privado/updater/resolve.go

@@ -0,0 +1,26 @@
+package updater
+
+import (
+	"time"
+
+	"github.com/qdm12/gluetun/internal/updater/resolver"
+)
+
+func parallelResolverSettings(hosts []string) (settings resolver.ParallelSettings) {
+	const (
+		maxFailRatio = 0.1
+		maxDuration  = 30 * time.Second
+		maxNoNew     = 2
+		maxFails     = 2
+	)
+	return resolver.ParallelSettings{
+		Hosts:        hosts,
+		MaxFailRatio: maxFailRatio,
+		Repeat: resolver.RepeatSettings{
+			MaxDuration: maxDuration,
+			MaxNoNew:    maxNoNew,
+			MaxFails:    maxFails,
+			SortIPs:     true,
+		},
+	}
+}

internal/provider/privado/updater/servers.go

@@ -2,66 +2,77 @@ package updater
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
-	"net/http"
-	"net/netip"
 	"sort"
+	"strings"
 
-	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/common"
+	"github.com/qdm12/gluetun/internal/updater/openvpn"
 )
 
 func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 	servers []models.Server, err error,
 ) {
-	const url = "https://privadovpn.com/apps/servers_export.json"
-	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
-	if err != nil {
-		return nil, fmt.Errorf("creating request: %w", err)
+	if !u.ipFetcher.CanFetchAnyIP() {
+		return nil, fmt.Errorf("%w: %s", common.ErrIPFetcherUnsupported, u.ipFetcher.String())
 	}
 
-	response, err := u.client.Do(request)
+	const url = "https://privadovpn.com/apps/ovpn_configs.zip"
+	contents, err := u.unzipper.FetchAndExtract(ctx, url)
+	if err != nil {
+		return nil, err
+	} else if len(contents) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(contents), minServers)
+	}
+
+	hts := make(hostToServer)
+
+	for fileName, content := range contents {
+		if !strings.HasSuffix(fileName, ".ovpn") {
+			continue // not an OpenVPN file
+		}
+
+		host, warning, err := openvpn.ExtractHost(content)
+		if warning != "" {
+			u.warner.Warn(warning)
+		}
+		if err != nil {
+			// treat error as warning and go to next file
+			u.warner.Warn(err.Error() + " in " + fileName)
+			continue
+		}
+
+		hts.add(host)
+	}
+
+	if len(hts) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(hts), minServers)
+	}
+
+	hosts := hts.toHostsSlice()
+	resolveSettings := parallelResolverSettings(hosts)
+	hostToIPs, warnings, err := u.parallelResolver.Resolve(ctx, resolveSettings)
+	for _, warning := range warnings {
+		u.warner.Warn(warning)
+	}
 	if err != nil {
 		return nil, err
 	}
 
-	var data struct {
-		Servers []struct {
-			Country  string     `json:"country"`
-			City     string     `json:"city"`
-			Hostname string     `json:"hostname"`
-			IP       netip.Addr `json:"ip"`
-		} `json:"servers"`
-	}
-	decoder := json.NewDecoder(response.Body)
-	err = decoder.Decode(&data)
-	if err != nil {
-		_ = response.Body.Close()
-		return nil, fmt.Errorf("decoding JSON response: %w", err)
-	}
-
-	err = response.Body.Close()
-	if err != nil {
-		return nil, fmt.Errorf("closing response body: %w", err)
-	}
-
-	if len(data.Servers) < minServers {
+	if len(hostToIPs) < minServers {
 		return nil, fmt.Errorf("%w: %d and expected at least %d",
-			common.ErrNotEnoughServers, len(data.Servers), minServers)
+			common.ErrNotEnoughServers, len(servers), minServers)
 	}
 
-	servers = make([]models.Server, len(data.Servers))
-	for i, server := range data.Servers {
-		servers[i] = models.Server{
-			VPN:      vpn.OpenVPN,
-			Country:  server.Country,
-			City:     server.City,
-			Hostname: server.Hostname,
-			IPs:      []netip.Addr{server.IP},
-			UDP:      true,
-		}
+	hts.adaptWithIPs(hostToIPs)
+
+	servers = hts.toServersSlice()
+
+	if err := setLocationInfo(ctx, u.ipFetcher, servers); err != nil {
+		return nil, err
 	}
 
 	sort.Sort(models.SortableServers(servers))

internal/provider/privado/updater/updater.go

@@ -1,19 +1,23 @@
 package updater
 
 import (
-	"net/http"
-
 	"github.com/qdm12/gluetun/internal/provider/common"
 )
 
 type Updater struct {
-	client *http.Client
+	ipFetcher        common.IPFetcher
+	unzipper         common.Unzipper
+	parallelResolver common.ParallelResolver
 	warner           common.Warner
 }
 
-func New(client *http.Client, warner common.Warner) *Updater {
+func New(ipFetcher common.IPFetcher, unzipper common.Unzipper,
+	warner common.Warner, parallelResolver common.ParallelResolver,
+) *Updater {
 	return &Updater{
-		client: client,
+		ipFetcher:        ipFetcher,
+		unzipper:         unzipper,
+		parallelResolver: parallelResolver,
 		warner:           warner,
 	}
 }