Merge branch 'master' into pmtu

- Add `VPN_PMTUD` option enabled by default
- One can revert to use `VPN_PMTUD=off` to disable the new PMTUD mechanism

.github/workflows/markdown.yml

@@ -20,7 +20,7 @@ jobs:
     steps:
       - uses: actions/checkout@v5
 
-      - uses: DavidAnson/markdownlint-cli2-action@v21
+      - uses: DavidAnson/markdownlint-cli2-action@v20
         with:
           globs: "**.md"
           config: .markdownlint-cli2.jsonc

.golangci.yml

@@ -56,9 +56,6 @@ linters:
           - revive
         path: internal\/provider\/(common|utils)\/.+\.go
         text: "var-naming: avoid (bad|meaningless) package names"
-      - linters:
-          - lll
-        source: "^// https://.+$"
       - linters:
           - err113
           - mnd

Dockerfile

@@ -167,19 +167,20 @@ ENV VPN_SERVICE_PROVIDER=pia \
     HEALTH_ICMP_TARGET_IP=1.1.1.1 \
     HEALTH_RESTART_VPN=on \
     # DNS
+    DNS_SERVER=on \
     DNS_UPSTREAM_RESOLVER_TYPE=DoT \
     DNS_UPSTREAM_RESOLVERS=cloudflare \
     DNS_BLOCK_IPS= \
-    DNS_BLOCK_IP_PREFIXES= \
+    DNS_BLOCK_IP_PREFIXES=127.0.0.1/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16,169.254.0.0/16,::1/128,fc00::/7,fe80::/10,::ffff:7f00:1/104,::ffff:a00:0/104,::ffff:a9fe:0/112,::ffff:ac10:0/108,::ffff:c0a8:0/112 \
     DNS_CACHING=on \
     DNS_UPSTREAM_IPV6=off \
     BLOCK_MALICIOUS=on \
     BLOCK_SURVEILLANCE=off \
     BLOCK_ADS=off \
     DNS_UNBLOCK_HOSTNAMES= \
-    DNS_REBINDING_PROTECTION_EXEMPT_HOSTNAMES= \
     DNS_UPDATE_PERIOD=24h \
-    DNS_UPSTREAM_PLAIN_ADDRESSES= \
+    DNS_ADDRESS=127.0.0.1 \
+    DNS_KEEP_NAMESERVER=off \
     # HTTP proxy
     HTTPPROXY= \
     HTTPPROXY_LOG=off \
@@ -200,13 +201,10 @@ ENV VPN_SERVICE_PROVIDER=pia \
     HTTP_CONTROL_SERVER_LOG=on \
     HTTP_CONTROL_SERVER_ADDRESS=":8000" \
     HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH=/gluetun/auth/config.toml \
-    HTTP_CONTROL_SERVER_AUTH_DEFAULT_ROLE="{}" \
     # Server data updater
     UPDATER_PERIOD=0 \
     UPDATER_MIN_RATIO=0.8 \
     UPDATER_VPN_SERVICE_PROVIDERS= \
-    UPDATER_PROTONVPN_USERNAME= \
-    UPDATER_PROTONVPN_PASSWORD= \
     # Public IP
     PUBLICIP_FILE="/tmp/gluetun/ip" \
     PUBLICIP_ENABLED=on \
@@ -222,8 +220,8 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Extras
     VERSION_INFORMATION=on \
     TZ= \
-    PUID=1000 \
+    PUID= \
-    PGID=1000
+    PGID=
 ENTRYPOINT ["/gluetun-entrypoint"]
 EXPOSE 8000/tcp 8888/tcp 8388/tcp 8388/udp
 HEALTHCHECK --interval=5s --timeout=5s --start-period=10s --retries=3 CMD /gluetun-entrypoint healthcheck

README.md

@@ -1,7 +1,5 @@
 # Gluetun VPN client
 
-⚠️ This and [gluetun-wiki](https://github.com/qdm12/gluetun-wiki) are the only websites for Gluetun, other websites claiming to be official are scams ⚠️
-
 Lightweight swiss-army-knife-like VPN client to multiple VPN service providers
 
 ![Title image](https://raw.githubusercontent.com/qdm12/gluetun/master/title.svg)

cmd/gluetun/main.go

@@ -427,8 +427,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	parallelResolver := resolver.NewParallelResolver(allSettings.Updater.DNSAddress)
 	openvpnFileExtractor := extract.New()
 	providers := provider.NewProviders(storage, time.Now, updaterLogger,
-		httpClient, unzipper, parallelResolver, publicIPLooper.Fetcher(),
+		httpClient, unzipper, parallelResolver, publicIPLooper.Fetcher(), openvpnFileExtractor)
-		openvpnFileExtractor, allSettings.Updater)
 
 	vpnLogger := logger.New(log.SetComponent("vpn"))
 	vpnLooper := vpn.NewLoop(allSettings.VPN, ipv6Supported, allSettings.Firewall.VPNInputPorts,
@@ -467,10 +466,13 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	go shadowsocksLooper.Run(shadowsocksCtx, shadowsocksDone)
 	otherGroupHandler.Add(shadowsocksHandler)
 
+	controlServerAddress := *allSettings.ControlServer.Address
+	controlServerLogging := *allSettings.ControlServer.Log
 	httpServerHandler, httpServerCtx, httpServerDone := goshutdown.NewGoRoutineHandler(
 		"http server", goroutine.OptionTimeout(defaultShutdownTimeout))
-	httpServer, err := server.New(httpServerCtx, allSettings.ControlServer,
+	httpServer, err := server.New(httpServerCtx, controlServerAddress, controlServerLogging,
 		logger.New(log.SetComponent("http server")),
+		allSettings.ControlServer.AuthFilePath,
 		buildInfo, vpnLooper, portForwardLooper, dnsLooper, updaterLooper, publicIPLooper,
 		storage, ipv6Supported)
 	if err != nil {
@@ -579,6 +581,7 @@ type Linker interface {
 	LinkDel(link netlink.Link) (err error)
 	LinkSetUp(link netlink.Link) (linkIndex int, err error)
 	LinkSetDown(link netlink.Link) (err error)
+	LinkSetMTU(link netlink.Link, mtu int) error
 }
 
 type clier interface {

go.mod

@@ -3,14 +3,13 @@ module github.com/qdm12/gluetun
 go 1.25.0
 
 require (
-	github.com/ProtonMail/go-srp v0.0.7
 	github.com/breml/rootcerts v0.3.3
 	github.com/fatih/color v1.18.0
 	github.com/golang/mock v1.6.0
 	github.com/klauspost/compress v1.18.1
 	github.com/klauspost/pgzip v1.2.6
 	github.com/pelletier/go-toml/v2 v2.2.4
-	github.com/qdm12/dns/v2 v2.0.0-rc9.0.20251114155417-248acd28339f
+	github.com/qdm12/dns/v2 v2.0.0-rc9
 	github.com/qdm12/gosettings v0.4.4
 	github.com/qdm12/goshutdown v0.3.0
 	github.com/qdm12/gosplash v0.2.0
@@ -22,21 +21,17 @@ require (
 	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/net v0.46.0
-	golang.org/x/sys v0.38.0
+	golang.org/x/sys v0.37.0
-	golang.org/x/text v0.31.0
+	golang.org/x/text v0.30.0
 	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
 )
 
 require (
-	github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf // indirect
-	github.com/ProtonMail/go-crypto v1.3.0-proton // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	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/josharian/native v1.1.0 // indirect
@@ -47,7 +42,6 @@ require (
 	github.com/mdlayher/socket v0.4.1 // 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
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.20.5 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
@@ -56,11 +50,10 @@ require (
 	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 v0.44.0 // indirect
+	golang.org/x/crypto v0.43.0 // indirect
-	golang.org/x/mod v0.29.0 // indirect
+	golang.org/x/mod v0.28.0 // indirect
-	golang.org/x/sync v0.18.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
-	golang.org/x/time v0.3.0 // indirect
+	golang.org/x/tools v0.37.0 // indirect
-	golang.org/x/tools v0.38.0 // 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

@@ -1,23 +1,9 @@
-github.com/ProtonMail/bcrypt v0.0.0-20210511135022-227b4adcab57/go.mod h1:HecWFHognK8GfRDGnFQbW/LiV7A3MX3gZVs45vk5h8I=
-github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf h1:yc9daCCYUefEs69zUkSzubzjBbL+cmOXgnmt9Fyd9ug=
-github.com/ProtonMail/bcrypt v0.0.0-20211005172633-e235017c1baf/go.mod h1:o0ESU9p83twszAU8LBeJKFAAMX14tISa0yk4Oo5TOqo=
-github.com/ProtonMail/go-crypto v0.0.0-20230321155629-9a39f2531310/go.mod h1:8TI4H3IbrackdNgv+92dI+rhpCaLqM0IfpgCgenFvRE=
-github.com/ProtonMail/go-crypto v1.3.0-proton h1:tAQKQRZX/73VmzK6yHSCaRUOvS/3OYSQzhXQsrR7yUM=
-github.com/ProtonMail/go-crypto v1.3.0-proton/go.mod h1:9whxjD8Rbs29b4XWbB8irEcE8KHMqaR2e7GWU1R+/PE=
-github.com/ProtonMail/go-srp v0.0.7 h1:Sos3Qk+th4tQR64vsxGIxYpN3rdnG9Wf9K4ZloC1JrI=
-github.com/ProtonMail/go-srp v0.0.7/go.mod h1:giCp+7qRnMIcCvI6V6U3S1lDDXDQYx2ewJ6F/9wdlJk=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/breml/rootcerts v0.3.3 h1://GnaRtQ/9BY2+GtMk2wtWxVdCRysiaPr5/xBwl7NKw=
 github.com/breml/rootcerts v0.3.3/go.mod h1:S/PKh+4d1HUn4HQovEB8hPJZO6pUZYrIhmXBhsegfXw=
-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/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=
-github.com/cronokirby/saferith v0.33.0 h1:TgoQlfsD4LIwx71+ChfRcIpjkw+RPOapDEVxa+LhwLo=
-github.com/cronokirby/saferith v0.33.0/go.mod h1:QKJhjoqUtBsXCAVEjw38mFqoi7DebT7kthcD7UzbnoA=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/fatih/color v1.18.0 h1:S8gINlzdQ840/4pfAwic/ZE0djQEH3wM94VfqLTZcOM=
@@ -57,8 +43,6 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
-github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+bR9r+8l63Y=
@@ -69,8 +53,8 @@ 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-rc9.0.20251114155417-248acd28339f h1:6wN5D9wACfmXDsQ366egVt0jXY4nqL/QnIwg4nWhXco=
+github.com/qdm12/dns/v2 v2.0.0-rc9 h1:qDzRkHr6993jknNB/ZOCnZOyIG6bsZcl2MIfdeUd0kI=
-github.com/qdm12/dns/v2 v2.0.0-rc9.0.20251114155417-248acd28339f/go.mod h1:98foWgXJZ+g8gJIuO+fdO+oWpFei5WShMFTeN4Im2lE=
+github.com/qdm12/dns/v2 v2.0.0-rc9/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=
@@ -100,72 +84,48 @@ github.com/vishvananda/netns v0.0.5/go.mod h1:SpkAiCQRtJ6TvvxPnOSyH3BMl6unz3xZla
 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=
-github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 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 v0.43.0 h1:dduJYIi3A3KOfdGOHX8AVZ/jGiyPa3IbBozJ5kNuE04=
-golang.org/x/crypto v0.7.0/go.mod h1:pYwdfH91IfpZVANVyUOhSIPZaFoJGxTFbZhFTx+dXZU=
+golang.org/x/crypto v0.43.0/go.mod h1:BFbav4mRNlXJL4wNeejLpWxB7wMbc79PdRGhWKncxR0=
-golang.org/x/crypto v0.44.0 h1:A97SsFvM3AIwEEmTBiaxPPTYpDC47w720rdiiUvgoAU=
-golang.org/x/crypto v0.44.0/go.mod h1:013i+Nw79BMiQiMsOPcVCB5ZIJbYkerPrGnOa00tvmc=
 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 v0.28.0 h1:gQBtGhjxykdjY9YhZpSlZIsbnaE2+PgjfLWUQTnoZ1U=
-golang.org/x/mod v0.8.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/mod v0.28.0/go.mod h1:yfB/L0NOf/kmEbXjzCPOx1iK1fRutOydrCMsqRhEBxI=
-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/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=
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.46.0 h1:giFlY12I07fugqwPuWJi68oOnpfqFnJIJzaIIm2JVV4=
-golang.org/x/net v0.6.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
-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/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 v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-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/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=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210510120138-977fb7262007/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-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 v0.37.0 h1:fdNQudmxPjkdUTPnLn5mdQv7Zwvbvpaxqs831goi9kQ=
-golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/sys v0.37.0/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=
-golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 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 v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
-golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
-golang.org/x/text v0.8.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/time v0.0.0-20220210224613-90d013bbcef8 h1:vVKdlvoWBphwdxWKrFZEuM0kGgGLxUOYcY4U/2Vjg44=
-golang.org/x/text v0.31.0 h1:aC8ghyu4JhP8VojJ2lEHBnochRno1sgL6nEi9WGFGMM=
+golang.org/x/time v0.0.0-20220210224613-90d013bbcef8/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
-golang.org/x/text v0.31.0/go.mod h1:tKRAlv61yKIjGGHX/4tP1LTbc13YSec1pxVEWXzfoeM=
-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=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 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 v0.37.0 h1:DVSRzp7FwePZW356yEAChSdNcQo6Nsp+fex1SUW09lE=
-golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
+golang.org/x/tools v0.37.0/go.mod h1:MBN5QPQtLMHVdvsbtarmTNukZDdgwdwlO5qGacAzF0w=
-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/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/nooplogger.go

@@ -7,4 +7,3 @@ func newNoopLogger() *noopLogger {
 }
 
 func (l *noopLogger) Info(string) {}
-func (l *noopLogger) Warn(string) {}

internal/cli/openvpnconfig.go

@@ -76,7 +76,7 @@ func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, reader *reader.Reader,
 	openvpnFileExtractor := extract.New()
 
 	providers := provider.NewProviders(storage, time.Now, warner, client,
-		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor, allSettings.Updater)
+		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
 	providerConf := providers.Get(allSettings.VPN.Provider.Name)
 	connection, err := providerConf.GetConnection(
 		allSettings.VPN.Provider.ServerSelection, ipv6Supported)

internal/cli/update.go

@@ -6,7 +6,6 @@ import (
 	"flag"
 	"fmt"
 	"net/http"
-	"slices"
 	"strings"
 	"time"
 
@@ -25,8 +24,6 @@ import (
 var (
 	ErrModeUnspecified     = errors.New("at least one of -enduser or -maintainer must be specified")
 	ErrNoProviderSpecified = errors.New("no provider was specified")
-	ErrUsernameMissing     = errors.New("username is required for this provider")
-	ErrPasswordMissing     = errors.New("password is required for this provider")
 )
 
 type UpdaterLogger interface {
@@ -38,7 +35,7 @@ type UpdaterLogger interface {
 func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) error {
 	options := settings.Updater{}
 	var endUserMode, maintainerMode, updateAll bool
-	var csvProviders, ipToken, protonUsername, protonPassword string
+	var csvProviders, ipToken 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,
@@ -50,8 +47,6 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	flagSet.BoolVar(&updateAll, "all", false, "Update servers for all VPN providers")
 	flagSet.StringVar(&csvProviders, "providers", "", "CSV string of VPN providers to update server data for")
 	flagSet.StringVar(&ipToken, "ip-token", "", "IP data service token (e.g. ipinfo.io) to use")
-	flagSet.StringVar(&protonUsername, "proton-username", "", "Username to use to authenticate with Proton")
-	flagSet.StringVar(&protonPassword, "proton-password", "", "Password to use to authenticate with Proton")
 	if err := flagSet.Parse(args); err != nil {
 		return err
 	}
@@ -69,11 +64,6 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		options.Providers = strings.Split(csvProviders, ",")
 	}
 
-	if slices.Contains(options.Providers, providers.Protonvpn) {
-		options.ProtonUsername = &protonUsername
-		options.ProtonPassword = &protonPassword
-	}
-
 	options.SetDefaults(options.Providers[0])
 
 	err := options.Validate()
@@ -81,11 +71,7 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 		return fmt.Errorf("options validation failed: %w", err)
 	}
 
-	serversDataPath := constants.ServersData
+	storage, err := storage.New(logger, constants.ServersData)
-	if maintainerMode {
-		serversDataPath = ""
-	}
-	storage, err := storage.New(logger, serversDataPath)
 	if err != nil {
 		return fmt.Errorf("creating servers storage: %w", err)
 	}
@@ -108,7 +94,7 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	openvpnFileExtractor := extract.New()
 
 	providers := provider.NewProviders(storage, time.Now, logger, httpClient,
-		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor, options)
+		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
 
 	updater := updater.New(httpClient, storage, providers, logger)
 	err = updater.UpdateServers(ctx, options.Providers, options.MinRatio)

internal/configuration/settings/deprecated.go

@@ -14,10 +14,6 @@ func readObsolete(r *reader.Reader) (warnings []string) {
 		"DOT_VALIDATION_LOGLEVEL":      "DOT_VALIDATION_LOGLEVEL is obsolete because DNSSEC validation is not implemented.",
 		"HEALTH_VPN_DURATION_INITIAL":  "HEALTH_VPN_DURATION_INITIAL is obsolete",
 		"HEALTH_VPN_DURATION_ADDITION": "HEALTH_VPN_DURATION_ADDITION is obsolete",
-		"DNS_SERVER":                   "DNS_SERVER is obsolete because the forwarding server is always enabled.",
-		"DOT":                          "DOT is obsolete because the forwarding server is always enabled.",
-		"DNS_KEEP_NAMESERVER": "DNS_KEEP_NAMESERVER is obsolete because the forwarding server is always used and " +
-			"forwards local names to private DNS resolvers found in /etc/resolv.conf",
 	}
 	sortedKeys := maps.Keys(keyToMessage)
 	slices.Sort(sortedKeys)

internal/configuration/settings/dns.go

@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"net/netip"
-	"slices"
 	"time"
 
 	"github.com/qdm12/dns/v2/pkg/provider"
@@ -14,25 +13,20 @@ import (
 	"github.com/qdm12/gotree"
 )
 
-const (
-	DNSUpstreamTypeDot   = "dot"
-	DNSUpstreamTypeDoh   = "doh"
-	DNSUpstreamTypePlain = "plain"
-)
-
 // DNS contains settings to configure DNS.
 type DNS struct {
-	// UpstreamType can be [dnsUpstreamTypeDot], [dnsUpstreamTypeDoh]
+	// ServerEnabled is true if the server should be running
-	// or [dnsUpstreamTypePlain]. It defaults to [dnsUpstreamTypeDot].
+	// and used. It defaults to true, and cannot be nil
+	// in the internal state.
+	ServerEnabled *bool
+	// UpstreamType can be dot or plain, and defaults to dot.
 	UpstreamType string `json:"upstream_type"`
 	// UpdatePeriod is the period to update DNS block lists.
 	// It can be set to 0 to disable the update.
 	// It defaults to 24h and cannot be nil in
 	// the internal state.
 	UpdatePeriod *time.Duration
-	// Providers is a list of DNS providers.
+	// Providers is a list of DNS providers
-	// It defaults to either ["cloudflare"] or [] if the
-	// UpstreamPlainAddresses field is set.
 	Providers []string `json:"providers"`
 	// Caching is true if the server should cache
 	// DNS responses.
@@ -42,23 +36,32 @@ type DNS struct {
 	// Blacklist contains settings to configure the filter
 	// block lists.
 	Blacklist DNSBlacklist
-	// UpstreamPlainAddresses are the upstream plaintext DNS resolver
+	// ServerAddress is the DNS server to use inside
-	// addresses to use by the built-in DNS server forwarder.
+	// the Go program and for the system.
-	// Note, if the upstream type is [dnsUpstreamTypePlain] these are merged
+	// It defaults to '127.0.0.1' to be used with the
-	// together with provider names set in the Providers field.
+	// local server. It cannot be the zero value in the internal
-	// If this field is set, the Providers field will default to the empty slice.
+	// state.
-	UpstreamPlainAddresses []netip.AddrPort
+	ServerAddress netip.Addr
+	// KeepNameserver is true if the existing DNS server
+	// found in /etc/resolv.conf should be used
+	// Note setting this to true will likely DNS traffic
+	// outside the VPN tunnel since it would go through
+	// the local DNS server of your Docker/Kubernetes
+	// configuration, which is likely not going through the tunnel.
+	// This will also disable the DNS forwarder server and the
+	// `ServerAddress` field will be ignored.
+	// It defaults to false and cannot be nil in the
+	// internal state.
+	KeepNameserver *bool
 }
 
 var (
 	ErrDNSUpstreamTypeNotValid = errors.New("DNS upstream type is not valid")
 	ErrDNSUpdatePeriodTooShort = errors.New("update period is too short")
-	ErrDNSUpstreamPlainNoIPv6  = errors.New("upstream plain addresses do not contain any IPv6 address")
-	ErrDNSUpstreamPlainNoIPv4  = errors.New("upstream plain addresses do not contain any IPv4 address")
 )
 
 func (d DNS) validate() (err error) {
-	if !helpers.IsOneOf(d.UpstreamType, DNSUpstreamTypeDot, DNSUpstreamTypeDoh, DNSUpstreamTypePlain) {
+	if !helpers.IsOneOf(d.UpstreamType, "dot", "doh", "plain") {
 		return fmt.Errorf("%w: %s", ErrDNSUpstreamTypeNotValid, d.UpstreamType)
 	}
 
@@ -76,18 +79,6 @@ func (d DNS) validate() (err error) {
 		}
 	}
 
-	if d.UpstreamType == DNSUpstreamTypePlain {
-		if *d.IPv6 && !slices.ContainsFunc(d.UpstreamPlainAddresses, func(addrPort netip.AddrPort) bool {
-			return addrPort.Addr().Is6()
-		}) {
-			return fmt.Errorf("%w: in %d addresses", ErrDNSUpstreamPlainNoIPv6, len(d.UpstreamPlainAddresses))
-		} else if !slices.ContainsFunc(d.UpstreamPlainAddresses, func(addrPort netip.AddrPort) bool {
-			return addrPort.Addr().Is4()
-		}) {
-			return fmt.Errorf("%w: in %d addresses", ErrDNSUpstreamPlainNoIPv4, len(d.UpstreamPlainAddresses))
-		}
-	}
-
 	err = d.Blacklist.validate()
 	if err != nil {
 		return err
@@ -98,13 +89,15 @@ func (d DNS) validate() (err error) {
 
 func (d *DNS) Copy() (copied DNS) {
 	return DNS{
-		UpstreamType:           d.UpstreamType,
+		ServerEnabled:  gosettings.CopyPointer(d.ServerEnabled),
-		UpdatePeriod:           gosettings.CopyPointer(d.UpdatePeriod),
+		UpstreamType:   d.UpstreamType,
-		Providers:              gosettings.CopySlice(d.Providers),
+		UpdatePeriod:   gosettings.CopyPointer(d.UpdatePeriod),
-		Caching:                gosettings.CopyPointer(d.Caching),
+		Providers:      gosettings.CopySlice(d.Providers),
-		IPv6:                   gosettings.CopyPointer(d.IPv6),
+		Caching:        gosettings.CopyPointer(d.Caching),
-		Blacklist:              d.Blacklist.copy(),
+		IPv6:           gosettings.CopyPointer(d.IPv6),
-		UpstreamPlainAddresses: d.UpstreamPlainAddresses,
+		Blacklist:      d.Blacklist.copy(),
+		ServerAddress:  d.ServerAddress,
+		KeepNameserver: gosettings.CopyPointer(d.KeepNameserver),
 	}
 }
 
@@ -112,17 +105,20 @@ func (d *DNS) Copy() (copied DNS) {
 // settings object with any field set in the other
 // settings.
 func (d *DNS) overrideWith(other DNS) {
+	d.ServerEnabled = gosettings.OverrideWithPointer(d.ServerEnabled, other.ServerEnabled)
 	d.UpstreamType = gosettings.OverrideWithComparable(d.UpstreamType, other.UpstreamType)
 	d.UpdatePeriod = gosettings.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
 	d.Providers = gosettings.OverrideWithSlice(d.Providers, other.Providers)
 	d.Caching = gosettings.OverrideWithPointer(d.Caching, other.Caching)
 	d.IPv6 = gosettings.OverrideWithPointer(d.IPv6, other.IPv6)
 	d.Blacklist.overrideWith(other.Blacklist)
-	d.UpstreamPlainAddresses = gosettings.OverrideWithSlice(d.UpstreamPlainAddresses, other.UpstreamPlainAddresses)
+	d.ServerAddress = gosettings.OverrideWithValidator(d.ServerAddress, other.ServerAddress)
+	d.KeepNameserver = gosettings.OverrideWithPointer(d.KeepNameserver, other.KeepNameserver)
 }
 
 func (d *DNS) setDefaults() {
-	d.UpstreamType = gosettings.DefaultComparable(d.UpstreamType, DNSUpstreamTypeDot)
+	d.ServerEnabled = gosettings.DefaultPointer(d.ServerEnabled, true)
+	d.UpstreamType = gosettings.DefaultComparable(d.UpstreamType, "dot")
 	const defaultUpdatePeriod = 24 * time.Hour
 	d.UpdatePeriod = gosettings.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
 	d.Providers = gosettings.DefaultSlice(d.Providers, []string{
@@ -131,53 +127,26 @@ func (d *DNS) setDefaults() {
 	d.Caching = gosettings.DefaultPointer(d.Caching, true)
 	d.IPv6 = gosettings.DefaultPointer(d.IPv6, false)
 	d.Blacklist.setDefaults()
-	d.UpstreamPlainAddresses = gosettings.DefaultSlice(d.UpstreamPlainAddresses, []netip.AddrPort{})
+	d.ServerAddress = gosettings.DefaultValidator(d.ServerAddress,
-}
+		netip.AddrFrom4([4]byte{127, 0, 0, 1}))
-
+	d.KeepNameserver = gosettings.DefaultPointer(d.KeepNameserver, false)
-func defaultDNSProviders() []string {
-	return []string{
-		provider.Cloudflare().Name,
-	}
 }
 
 func (d DNS) GetFirstPlaintextIPv4() (ipv4 netip.Addr) {
-	if d.UpstreamType == DNSUpstreamTypePlain {
+	localhost := netip.AddrFrom4([4]byte{127, 0, 0, 1})
-		for _, addrPort := range d.UpstreamPlainAddresses {
+	if d.ServerAddress.Compare(localhost) != 0 && d.ServerAddress.Is4() {
-			if addrPort.Addr().Is4() {
+		return d.ServerAddress
-				return addrPort.Addr()
-			}
-		}
 	}
 
-	ipv4 = findPlainIPv4InProviders(d.Providers)
-	if ipv4.IsValid() {
-		return ipv4
-	}
-
-	// Either:
-	// - all upstream plain addresses are IPv6 and no provider is set
-	// - all providers set do not have a plaintext IPv4 address
-	ipv4 = findPlainIPv4InProviders(defaultDNSProviders())
-	if !ipv4.IsValid() {
-		panic("no plaintext IPv4 address found in default DNS providers")
-	}
-	return ipv4
-}
-
-func findPlainIPv4InProviders(providerNames []string) netip.Addr {
 	providers := provider.NewProviders()
-	for _, name := range providerNames {
+	provider, err := providers.Get(d.Providers[0])
-		provider, err := providers.Get(name)
+	if err != nil {
-		if err != nil {
+		// Settings should be validated before calling this function,
-			// Settings should be validated before calling this function,
+		// so an error happening here is a programming error.
-			// so an error happening here is a programming error.
+		panic(err)
-			panic(err)
-		}
-		if len(provider.Plain.IPv4) > 0 {
-			return provider.Plain.IPv4[0].Addr()
-		}
 	}
-	return netip.Addr{}
+
+	return provider.Plain.IPv4[0].Addr()
 }
 
 func (d DNS) String() string {
@@ -186,22 +155,22 @@ func (d DNS) String() string {
 
 func (d DNS) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("DNS settings:")
+	node.Appendf("Keep existing nameserver(s): %s", gosettings.BoolToYesNo(d.KeepNameserver))
+	if *d.KeepNameserver {
+		return node
+	}
+	node.Appendf("DNS server address to use: %s", d.ServerAddress)
+
+	node.Appendf("DNS forwarder server enabled: %s", gosettings.BoolToYesNo(d.ServerEnabled))
+	if !*d.ServerEnabled {
+		return node
+	}
 
 	node.Appendf("Upstream resolver type: %s", d.UpstreamType)
 
 	upstreamResolvers := node.Append("Upstream resolvers:")
-	if len(d.UpstreamPlainAddresses) > 0 {
+	for _, provider := range d.Providers {
-		if d.UpstreamType == DNSUpstreamTypePlain {
+		upstreamResolvers.Append(provider)
-			for _, addr := range d.UpstreamPlainAddresses {
-				upstreamResolvers.Append(addr.String())
-			}
-		} else {
-			node.Appendf("Upstream plain addresses: ignored because upstream type is not plain")
-		}
-	} else {
-		for _, provider := range d.Providers {
-			upstreamResolvers.Append(provider)
-		}
 	}
 
 	node.Appendf("Caching: %s", gosettings.BoolToYesNo(d.Caching))
@@ -219,6 +188,11 @@ func (d DNS) toLinesNode() (node *gotree.Node) {
 }
 
 func (d *DNS) read(r *reader.Reader) (err error) {
+	d.ServerEnabled, err = r.BoolPtr("DNS_SERVER", reader.RetroKeys("DOT"))
+	if err != nil {
+		return err
+	}
+
 	d.UpstreamType = r.String("DNS_UPSTREAM_RESOLVER_TYPE")
 
 	d.UpdatePeriod, err = r.DurationPtr("DNS_UPDATE_PERIOD")
@@ -243,43 +217,15 @@ func (d *DNS) read(r *reader.Reader) (err error) {
 		return err
 	}
 
-	err = d.readUpstreamPlainAddresses(r)
+	d.ServerAddress, err = r.NetipAddr("DNS_ADDRESS", reader.RetroKeys("DNS_PLAINTEXT_ADDRESS"))
+	if err != nil {
+		return err
+	}
+
+	d.KeepNameserver, err = r.BoolPtr("DNS_KEEP_NAMESERVER")
 	if err != nil {
 		return err
 	}
 
 	return nil
 }
-
-func (d *DNS) readUpstreamPlainAddresses(r *reader.Reader) (err error) {
-	// If DNS_UPSTREAM_PLAIN_ADDRESSES is set, the user must also set DNS_UPSTREAM_TYPE=plain
-	// for these to be used. This is an added safety measure to reduce misunderstandings, and
-	// reduce odd settings overrides.
-	d.UpstreamPlainAddresses, err = r.CSVNetipAddrPorts("DNS_UPSTREAM_PLAIN_ADDRESSES")
-	if err != nil {
-		return err
-	}
-
-	// Retro-compatibility - remove in v4
-	// If DNS_ADDRESS is set to a non-localhost address, append it to the other
-	// upstream plain addresses, assuming port 53, and force the upstream type to plain AND
-	// clear any user picked providers, to maintain retro-compatibility behavior.
-	serverAddress, err := r.NetipAddr("DNS_ADDRESS",
-		reader.RetroKeys("DNS_PLAINTEXT_ADDRESS"),
-		reader.IsRetro("DNS_UPSTREAM_PLAIN_ADDRESSES"))
-	if err != nil {
-		return err
-	} else if !serverAddress.IsValid() {
-		return nil
-	}
-	isLocalhost := serverAddress.Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) == 0
-	if isLocalhost {
-		return nil
-	}
-	const defaultPlainPort = 53
-	addrPort := netip.AddrPortFrom(serverAddress, defaultPlainPort)
-	d.UpstreamPlainAddresses = append(d.UpstreamPlainAddresses, addrPort)
-	d.UpstreamType = DNSUpstreamTypePlain
-	d.Providers = []string{}
-	return nil
-}

internal/configuration/settings/dns_test.go

@@ -1,26 +0,0 @@
-package settings
-
-import (
-	"testing"
-
-	"github.com/qdm12/dns/v2/pkg/provider"
-	"github.com/stretchr/testify/require"
-)
-
-func Test_defaultDNSProviders(t *testing.T) {
-	t.Parallel()
-
-	names := defaultDNSProviders()
-
-	found := false
-	providers := provider.NewProviders()
-	for _, name := range names {
-		provider, err := providers.Get(name)
-		require.NoError(t, err)
-		if len(provider.Plain.IPv4) > 0 {
-			found = true
-			break
-		}
-	}
-	require.True(t, found, "no default DNS provider has a plaintext IPv4 address")
-}

internal/configuration/settings/dnsblacklist.go

@@ -22,9 +22,6 @@ type DNSBlacklist struct {
 	AddBlockedHosts      []string
 	AddBlockedIPs        []netip.Addr
 	AddBlockedIPPrefixes []netip.Prefix
-	// RebindingProtectionExemptHostnames is a list of hostnames
-	// exempt from DNS rebinding protection.
-	RebindingProtectionExemptHostnames []string
 }
 
 func (b *DNSBlacklist) setDefaults() {
@@ -36,9 +33,8 @@ func (b *DNSBlacklist) setDefaults() {
 var hostRegex = regexp.MustCompile(`^([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9_])(\.([a-zA-Z0-9]|[a-zA-Z0-9_][a-zA-Z0-9\-_]{0,61}[a-zA-Z0-9]))*$`) //nolint:lll
 
 var (
-	ErrAllowedHostNotValid                   = errors.New("allowed host is not valid")
+	ErrAllowedHostNotValid = errors.New("allowed host is not valid")
-	ErrBlockedHostNotValid                   = errors.New("blocked host is not valid")
+	ErrBlockedHostNotValid = errors.New("blocked host is not valid")
-	ErrRebindingProtectionExemptHostNotValid = errors.New("rebinding protection exempt host is not valid")
 )
 
 func (b DNSBlacklist) validate() (err error) {
@@ -54,25 +50,18 @@ func (b DNSBlacklist) validate() (err error) {
 		}
 	}
 
-	for _, host := range b.RebindingProtectionExemptHostnames {
-		if !hostRegex.MatchString(host) {
-			return fmt.Errorf("%w: %s", ErrRebindingProtectionExemptHostNotValid, host)
-		}
-	}
-
 	return nil
 }
 
 func (b DNSBlacklist) copy() (copied DNSBlacklist) {
 	return DNSBlacklist{
-		BlockMalicious:                     gosettings.CopyPointer(b.BlockMalicious),
+		BlockMalicious:       gosettings.CopyPointer(b.BlockMalicious),
-		BlockAds:                           gosettings.CopyPointer(b.BlockAds),
+		BlockAds:             gosettings.CopyPointer(b.BlockAds),
-		BlockSurveillance:                  gosettings.CopyPointer(b.BlockSurveillance),
+		BlockSurveillance:    gosettings.CopyPointer(b.BlockSurveillance),
-		AllowedHosts:                       gosettings.CopySlice(b.AllowedHosts),
+		AllowedHosts:         gosettings.CopySlice(b.AllowedHosts),
-		AddBlockedHosts:                    gosettings.CopySlice(b.AddBlockedHosts),
+		AddBlockedHosts:      gosettings.CopySlice(b.AddBlockedHosts),
-		AddBlockedIPs:                      gosettings.CopySlice(b.AddBlockedIPs),
+		AddBlockedIPs:        gosettings.CopySlice(b.AddBlockedIPs),
-		AddBlockedIPPrefixes:               gosettings.CopySlice(b.AddBlockedIPPrefixes),
+		AddBlockedIPPrefixes: gosettings.CopySlice(b.AddBlockedIPPrefixes),
-		RebindingProtectionExemptHostnames: gosettings.CopySlice(b.RebindingProtectionExemptHostnames),
 	}
 }
 
@@ -84,8 +73,6 @@ func (b *DNSBlacklist) overrideWith(other DNSBlacklist) {
 	b.AddBlockedHosts = gosettings.OverrideWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
 	b.AddBlockedIPs = gosettings.OverrideWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
 	b.AddBlockedIPPrefixes = gosettings.OverrideWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
-	b.RebindingProtectionExemptHostnames = gosettings.OverrideWithSlice(b.RebindingProtectionExemptHostnames,
-		other.RebindingProtectionExemptHostnames)
 }
 
 func (b DNSBlacklist) ToBlockBuilderSettings(client *http.Client) (
@@ -142,13 +129,6 @@ func (b DNSBlacklist) toLinesNode() (node *gotree.Node) {
 		}
 	}
 
-	if len(b.RebindingProtectionExemptHostnames) > 0 {
-		exemptHostsNode := node.Append("Rebinding protection exempt hostnames:")
-		for _, host := range b.RebindingProtectionExemptHostnames {
-			exemptHostsNode.Append(host)
-		}
-	}
-
 	return node
 }
 
@@ -176,8 +156,6 @@ func (b *DNSBlacklist) read(r *reader.Reader) (err error) {
 
 	b.AllowedHosts = r.CSV("DNS_UNBLOCK_HOSTNAMES", reader.RetroKeys("UNBLOCK"))
 
-	b.RebindingProtectionExemptHostnames = r.CSV("DNS_REBINDING_PROTECTION_EXEMPT_HOSTNAMES")
-
 	return nil
 }
 

internal/configuration/settings/errors.go

@@ -36,8 +36,6 @@ var (
 	ErrSystemPUIDNotValid              = errors.New("process user id is not valid")
 	ErrSystemTimezoneNotValid          = errors.New("timezone is not valid")
 	ErrUpdaterPeriodTooSmall           = errors.New("VPN server data updater period is too small")
-	ErrUpdaterProtonPasswordMissing    = errors.New("proton password is missing")
-	ErrUpdaterProtonUsernameMissing    = errors.New("proton username is missing")
 	ErrVPNProviderNameNotValid         = errors.New("VPN provider name is not valid")
 	ErrVPNTypeNotValid                 = errors.New("VPN type is not valid")
 	ErrWireguardAllowedIPNotSet        = errors.New("allowed IP is not set")

internal/configuration/settings/health.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/netip"
 	"os"
+	"time"
 
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/reader"
@@ -17,6 +18,12 @@ type Health struct {
 	// for the health check server.
 	// It cannot be the empty string in the internal state.
 	ServerAddress string
+	// ReadHeaderTimeout is the HTTP server header read timeout
+	// duration of the HTTP server. It defaults to 100 milliseconds.
+	ReadHeaderTimeout time.Duration
+	// ReadTimeout is the HTTP read timeout duration of the
+	// HTTP server. It defaults to 500 milliseconds.
+	ReadTimeout time.Duration
 	// TargetAddress is the address (host or host:port)
 	// to TCP TLS dial to periodically for the health check.
 	// It cannot be the empty string in the internal state.
@@ -41,10 +48,12 @@ func (h Health) Validate() (err error) {
 
 func (h *Health) copy() (copied Health) {
 	return Health{
-		ServerAddress: h.ServerAddress,
+		ServerAddress:     h.ServerAddress,
-		TargetAddress: h.TargetAddress,
+		ReadHeaderTimeout: h.ReadHeaderTimeout,
-		ICMPTargetIP:  h.ICMPTargetIP,
+		ReadTimeout:       h.ReadTimeout,
-		RestartVPN:    gosettings.CopyPointer(h.RestartVPN),
+		TargetAddress:     h.TargetAddress,
+		ICMPTargetIP:      h.ICMPTargetIP,
+		RestartVPN:        gosettings.CopyPointer(h.RestartVPN),
 	}
 }
 
@@ -53,6 +62,8 @@ func (h *Health) copy() (copied Health) {
 // settings.
 func (h *Health) OverrideWith(other Health) {
 	h.ServerAddress = gosettings.OverrideWithComparable(h.ServerAddress, other.ServerAddress)
+	h.ReadHeaderTimeout = gosettings.OverrideWithComparable(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = gosettings.OverrideWithComparable(h.ReadTimeout, other.ReadTimeout)
 	h.TargetAddress = gosettings.OverrideWithComparable(h.TargetAddress, other.TargetAddress)
 	h.ICMPTargetIP = gosettings.OverrideWithComparable(h.ICMPTargetIP, other.ICMPTargetIP)
 	h.RestartVPN = gosettings.OverrideWithPointer(h.RestartVPN, other.RestartVPN)
@@ -60,6 +71,10 @@ func (h *Health) OverrideWith(other Health) {
 
 func (h *Health) SetDefaults() {
 	h.ServerAddress = gosettings.DefaultComparable(h.ServerAddress, "127.0.0.1:9999")
+	const defaultReadHeaderTimeout = 100 * time.Millisecond
+	h.ReadHeaderTimeout = gosettings.DefaultComparable(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
+	const defaultReadTimeout = 500 * time.Millisecond
+	h.ReadTimeout = gosettings.DefaultComparable(h.ReadTimeout, defaultReadTimeout)
 	h.TargetAddress = gosettings.DefaultComparable(h.TargetAddress, "cloudflare.com:443")
 	h.ICMPTargetIP = gosettings.DefaultComparable(h.ICMPTargetIP, netip.IPv4Unspecified()) // use the VPN server IP
 	h.RestartVPN = gosettings.DefaultPointer(h.RestartVPN, true)

internal/configuration/settings/server.go

@@ -1,14 +1,11 @@
 package settings
 
 import (
-	"bytes"
-	"encoding/json"
 	"fmt"
 	"net"
 	"os"
 	"strconv"
 
-	"github.com/qdm12/gluetun/internal/server/middlewares/auth"
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/reader"
 	"github.com/qdm12/gotree"
@@ -27,9 +24,6 @@ type ControlServer struct {
 	// It cannot be empty in the internal state and defaults to
 	// /gluetun/auth/config.toml.
 	AuthFilePath string
-	// AuthDefaultRole is a JSON encoded object defining the default role
-	// that applies to all routes without a previously user-defined role assigned to.
-	AuthDefaultRole string
 }
 
 func (c ControlServer) validate() (err error) {
@@ -50,30 +44,14 @@ func (c ControlServer) validate() (err error) {
 			ErrControlServerPrivilegedPort, port, uid)
 	}
 
-	jsonDecoder := json.NewDecoder(bytes.NewBufferString(c.AuthDefaultRole))
-	jsonDecoder.DisallowUnknownFields()
-	var role auth.Role
-	err = jsonDecoder.Decode(&role)
-	if err != nil {
-		return fmt.Errorf("default authentication role is not valid JSON: %w", err)
-	}
-
-	if role.Auth != "" {
-		err = role.Validate()
-		if err != nil {
-			return fmt.Errorf("default authentication role is not valid: %w", err)
-		}
-	}
-
 	return nil
 }
 
 func (c *ControlServer) copy() (copied ControlServer) {
 	return ControlServer{
-		Address:         gosettings.CopyPointer(c.Address),
+		Address:      gosettings.CopyPointer(c.Address),
-		Log:             gosettings.CopyPointer(c.Log),
+		Log:          gosettings.CopyPointer(c.Log),
-		AuthFilePath:    c.AuthFilePath,
+		AuthFilePath: c.AuthFilePath,
-		AuthDefaultRole: c.AuthDefaultRole,
 	}
 }
 
@@ -84,21 +62,12 @@ func (c *ControlServer) overrideWith(other ControlServer) {
 	c.Address = gosettings.OverrideWithPointer(c.Address, other.Address)
 	c.Log = gosettings.OverrideWithPointer(c.Log, other.Log)
 	c.AuthFilePath = gosettings.OverrideWithComparable(c.AuthFilePath, other.AuthFilePath)
-	c.AuthDefaultRole = gosettings.OverrideWithComparable(c.AuthDefaultRole, other.AuthDefaultRole)
 }
 
 func (c *ControlServer) setDefaults() {
 	c.Address = gosettings.DefaultPointer(c.Address, ":8000")
 	c.Log = gosettings.DefaultPointer(c.Log, true)
 	c.AuthFilePath = gosettings.DefaultComparable(c.AuthFilePath, "/gluetun/auth/config.toml")
-	c.AuthDefaultRole = gosettings.DefaultComparable(c.AuthDefaultRole, "{}")
-	if c.AuthDefaultRole != "{}" {
-		var role auth.Role
-		_ = json.Unmarshal([]byte(c.AuthDefaultRole), &role)
-		role.Name = "default"
-		roleBytes, _ := json.Marshal(role) //nolint:errchkjson
-		c.AuthDefaultRole = string(roleBytes)
-	}
 }
 
 func (c ControlServer) String() string {
@@ -110,11 +79,6 @@ func (c ControlServer) toLinesNode() (node *gotree.Node) {
 	node.Appendf("Listening address: %s", *c.Address)
 	node.Appendf("Logging: %s", gosettings.BoolToYesNo(c.Log))
 	node.Appendf("Authentication file path: %s", c.AuthFilePath)
-	if c.AuthDefaultRole != "{}" {
-		var role auth.Role
-		_ = json.Unmarshal([]byte(c.AuthDefaultRole), &role)
-		node.AppendNode(role.ToLinesNode())
-	}
 	return node
 }
 
@@ -127,7 +91,6 @@ func (c *ControlServer) read(r *reader.Reader) (err error) {
 	c.Address = r.Get("HTTP_CONTROL_SERVER_ADDRESS")
 
 	c.AuthFilePath = r.String("HTTP_CONTROL_SERVER_AUTH_CONFIG_FILEPATH")
-	c.AuthDefaultRole = r.String("HTTP_CONTROL_SERVER_AUTH_DEFAULT_ROLE")
 
 	return nil
 }

internal/configuration/settings/settings.go

@@ -2,6 +2,7 @@ package settings
 
 import (
 	"fmt"
+	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
@@ -173,11 +174,13 @@ func (s Settings) Warnings() (warnings []string) {
 			"by creating an issue, attaching the new certificate and we will update Gluetun.")
 	}
 
-	for _, upstreamAddress := range s.DNS.UpstreamPlainAddresses {
+	// TODO remove in v4
-		if upstreamAddress.Addr().IsPrivate() {
+	if s.DNS.ServerAddress.Unmap().Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
-			warnings = append(warnings, "DNS upstream address "+upstreamAddress.String()+" is private: "+
+		warnings = append(warnings, "DNS address is set to "+s.DNS.ServerAddress.String()+
-				"DNS traffic might leak out of the VPN tunnel to that address.")
+			" so the local forwarding DNS server will not be used."+
-		}
+			" The default value changed to 127.0.0.1 so it uses the internal DNS server."+
+			" If this server fails to start, the IPv4 address of the first plaintext DNS server"+
+			" corresponding to the first DNS provider chosen is used.")
 	}
 
 	return warnings

internal/configuration/settings/settings_test.go

@@ -38,6 +38,9 @@ func Test_Settings_String(t *testing.T) {
 |       ├── Run OpenVPN as: root
 |       └── Verbosity level: 1
 ├── DNS settings:
+|   ├── Keep existing nameserver(s): no
+|   ├── DNS server address to use: 127.0.0.1
+|   ├── DNS forwarder server enabled: yes
 |   ├── Upstream resolver type: dot
 |   ├── Upstream resolvers:
 |   |   └── Cloudflare

internal/configuration/settings/updater.go

@@ -2,7 +2,6 @@ package settings
 
 import (
 	"fmt"
-	"slices"
 	"strings"
 	"time"
 
@@ -32,10 +31,6 @@ type Updater struct {
 	// Providers is the list of VPN service providers
 	// to update server information for.
 	Providers []string
-	// ProtonUsername is the username to authenticate with the Proton API.
-	ProtonUsername *string
-	// ProtonPassword is the password to authenticate with the Proton API.
-	ProtonPassword *string
 }
 
 func (u Updater) Validate() (err error) {
@@ -56,18 +51,6 @@ func (u Updater) Validate() (err error) {
 		if err != nil {
 			return fmt.Errorf("%w: %w", ErrVPNProviderNameNotValid, err)
 		}
-
-		if provider == providers.Protonvpn {
-			authenticatedAPI := *u.ProtonUsername != "" || *u.ProtonPassword != ""
-			if authenticatedAPI {
-				switch {
-				case *u.ProtonUsername == "":
-					return fmt.Errorf("%w", ErrUpdaterProtonUsernameMissing)
-				case *u.ProtonPassword == "":
-					return fmt.Errorf("%w", ErrUpdaterProtonPasswordMissing)
-				}
-			}
-		}
 	}
 
 	return nil
@@ -75,12 +58,10 @@ func (u Updater) Validate() (err error) {
 
 func (u *Updater) copy() (copied Updater) {
 	return Updater{
-		Period:         gosettings.CopyPointer(u.Period),
+		Period:     gosettings.CopyPointer(u.Period),
-		DNSAddress:     u.DNSAddress,
+		DNSAddress: u.DNSAddress,
-		MinRatio:       u.MinRatio,
+		MinRatio:   u.MinRatio,
-		Providers:      gosettings.CopySlice(u.Providers),
+		Providers:  gosettings.CopySlice(u.Providers),
-		ProtonUsername: gosettings.CopyPointer(u.ProtonUsername),
-		ProtonPassword: gosettings.CopyPointer(u.ProtonPassword),
 	}
 }
 
@@ -92,8 +73,6 @@ func (u *Updater) overrideWith(other Updater) {
 	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.ProtonUsername = gosettings.OverrideWithPointer(u.ProtonUsername, other.ProtonUsername)
-	u.ProtonPassword = gosettings.OverrideWithPointer(u.ProtonPassword, other.ProtonPassword)
 }
 
 func (u *Updater) SetDefaults(vpnProvider string) {
@@ -108,10 +87,6 @@ func (u *Updater) SetDefaults(vpnProvider string) {
 	if len(u.Providers) == 0 && vpnProvider != providers.Custom {
 		u.Providers = []string{vpnProvider}
 	}
-
-	// Set these to empty strings to avoid nil pointer panics
-	u.ProtonUsername = gosettings.DefaultPointer(u.ProtonUsername, "")
-	u.ProtonPassword = gosettings.DefaultPointer(u.ProtonPassword, "")
 }
 
 func (u Updater) String() string {
@@ -128,10 +103,6 @@ func (u Updater) toLinesNode() (node *gotree.Node) {
 	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) {
-		node.Appendf("Proton API username: %s", *u.ProtonUsername)
-		node.Appendf("Proton API password: %s", gosettings.ObfuscateKey(*u.ProtonPassword))
-	}
 
 	return node
 }
@@ -154,14 +125,6 @@ func (u *Updater) read(r *reader.Reader) (err error) {
 
 	u.Providers = r.CSV("UPDATER_VPN_SERVICE_PROVIDERS")
 
-	u.ProtonUsername = r.Get("UPDATER_PROTONVPN_USERNAME")
-	if u.ProtonUsername != nil {
-		// Enforce to use the username not the email address
-		*u.ProtonUsername = strings.TrimSuffix(*u.ProtonUsername, "@protonmail.com")
-		*u.ProtonUsername = strings.TrimSuffix(*u.ProtonUsername, "@proton.me")
-	}
-	u.ProtonPassword = r.Get("UPDATER_PROTONVPN_PASSWORD")
-
 	return nil
 }
 

internal/configuration/settings/wireguard.go

@@ -45,6 +45,7 @@ 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.
+	// Note this should now be replaced with the PMTUD feature.
 	MTU uint16 `json:"mtu"`
 	// Implementation is the Wireguard implementation to use.
 	// It can be "auto", "userspace" or "kernelspace".

internal/configuration/settings/wireguardselection.go

@@ -155,8 +155,7 @@ func (w WireguardSelection) toLinesNode() (node *gotree.Node) {
 func (w *WireguardSelection) read(r *reader.Reader) (err error) {
 	w.EndpointIP, err = r.NetipAddr("WIREGUARD_ENDPOINT_IP", reader.RetroKeys("VPN_ENDPOINT_IP"))
 	if err != nil {
-		return fmt.Errorf("%w - note this MUST be an IP address, "+
+		return err
-			"see https://github.com/qdm12/gluetun/issues/788", err)
 	}
 
 	w.EndpointPort, err = r.Uint16Ptr("WIREGUARD_ENDPOINT_PORT", reader.RetroKeys("VPN_ENDPOINT_PORT"))

internal/dns/loop.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"fmt"
 	"net/http"
-	"net/netip"
 	"time"
 
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/mapfilter"
@@ -17,23 +16,22 @@ import (
 )
 
 type Loop struct {
-	statusManager  *loopstate.State
+	statusManager *loopstate.State
-	state          *state.State
+	state         *state.State
-	server         *server.Server
+	server        *server.Server
-	filter         *mapfilter.Filter
+	filter        *mapfilter.Filter
-	localResolvers []netip.Addr
+	resolvConf    string
-	resolvConf     string
+	client        *http.Client
-	client         *http.Client
+	logger        Logger
-	logger         Logger
+	userTrigger   bool
-	userTrigger    bool
+	start         <-chan struct{}
-	start          <-chan struct{}
+	running       chan<- models.LoopStatus
-	running        chan<- models.LoopStatus
+	stop          <-chan struct{}
-	stop           <-chan struct{}
+	stopped       chan<- struct{}
-	stopped        chan<- struct{}
+	updateTicker  <-chan struct{}
-	updateTicker   <-chan struct{}
+	backoffTime   time.Duration
-	backoffTime    time.Duration
+	timeNow       func() time.Time
-	timeNow        func() time.Time
+	timeSince     func(time.Time) time.Duration
-	timeSince      func(time.Time) time.Duration
 }
 
 const defaultBackoffTime = 10 * time.Second
@@ -50,9 +48,7 @@ func NewLoop(settings settings.DNS,
 	statusManager := loopstate.New(constants.Stopped, start, running, stop, stopped)
 	state := state.New(statusManager, settings, updateTicker)
 
-	filter, err := mapfilter.New(mapfilter.Settings{
+	filter, err := mapfilter.New(mapfilter.Settings{})
-		Logger: buildFilterLogger(logger),
-	})
 	if err != nil {
 		return nil, fmt.Errorf("creating map filter: %w", err)
 	}
@@ -104,15 +100,3 @@ func (l *Loop) signalOrSetStatus(status models.LoopStatus) {
 		l.statusManager.SetStatus(status)
 	}
 }
-
-type filterLogger struct {
-	logger Logger
-}
-
-func (l *filterLogger) Log(msg string) {
-	l.logger.Info(msg)
-}
-
-func buildFilterLogger(logger Logger) *filterLogger {
-	return &filterLogger{logger: logger}
-}

internal/dns/run.go

@@ -4,23 +4,21 @@ import (
 	"context"
 	"errors"
 
-	"github.com/qdm12/dns/v2/pkg/nameserver"
 	"github.com/qdm12/gluetun/internal/constants"
 )
 
 func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 	defer close(done)
 
-	var err error
+	if *l.GetSettings().KeepNameserver {
-	l.localResolvers, err = nameserver.GetPrivateDNSServers()
+		l.logger.Warn("⚠️⚠️⚠️  keeping the default container nameservers, " +
-	if err != nil {
+			"this will likely leak DNS traffic outside the VPN " +
-		l.logger.Error("getting private DNS servers: " + err.Error())
+			"and go through your container network DNS outside the VPN tunnel!")
-		return
+	} else {
+		const fallback = false
+		l.useUnencryptedDNS(fallback)
 	}
 
-	const fallback = false
-	l.useUnencryptedDNS(fallback)
-
 	select {
 	case <-l.start:
 	case <-ctx.Done():
@@ -32,12 +30,14 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 		// Their values are to be used if DOT=off
 		var runError <-chan error
 
-		for {
+		settings := l.GetSettings()
+		for !*settings.KeepNameserver && *settings.ServerEnabled {
 			var err error
 			runError, err = l.setupServer(ctx)
 			if err == nil {
 				l.backoffTime = defaultBackoffTime
 				l.logger.Info("ready")
+				l.signalOrSetStatus(constants.Running)
 				break
 			}
 
@@ -52,11 +52,14 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 				l.useUnencryptedDNS(fallback)
 			}
 			l.logAndWait(ctx, err)
+			settings = l.GetSettings()
 		}
-		l.signalOrSetStatus(constants.Running)
 
-		const fallback = false
+		settings = l.GetSettings()
-		l.useUnencryptedDNS(fallback)
+		if !*settings.KeepNameserver && !*settings.ServerEnabled {
+			const fallback = false
+			l.useUnencryptedDNS(fallback)
+		}
 
 		l.userTrigger = false
 

internal/dns/settings.go

@@ -3,7 +3,6 @@ package dns
 import (
 	"context"
 	"fmt"
-	"net/netip"
 
 	"github.com/qdm12/dns/v2/pkg/doh"
 	"github.com/qdm12/dns/v2/pkg/dot"
@@ -11,7 +10,6 @@ import (
 	"github.com/qdm12/dns/v2/pkg/middlewares/cache/lru"
 	filtermiddleware "github.com/qdm12/dns/v2/pkg/middlewares/filter"
 	"github.com/qdm12/dns/v2/pkg/middlewares/filter/mapfilter"
-	"github.com/qdm12/dns/v2/pkg/middlewares/localdns"
 	"github.com/qdm12/dns/v2/pkg/plain"
 	"github.com/qdm12/dns/v2/pkg/provider"
 	"github.com/qdm12/dns/v2/pkg/server"
@@ -26,23 +24,30 @@ func (l *Loop) SetSettings(ctx context.Context, settings settings.DNS) (
 	return l.state.SetSettings(ctx, settings)
 }
 
-func buildServerSettings(userSettings settings.DNS,
+func buildServerSettings(settings settings.DNS,
-	filter *mapfilter.Filter, localResolvers []netip.Addr,
+	filter *mapfilter.Filter, logger Logger) (
-	logger Logger) (
 	serverSettings server.Settings, err error,
 ) {
 	serverSettings.Logger = logger
 
-	upstreamResolvers := buildProviders(userSettings)
+	providersData := provider.NewProviders()
+	upstreamResolvers := make([]provider.Provider, len(settings.Providers))
+	for i := range settings.Providers {
+		var err error
+		upstreamResolvers[i], err = providersData.Get(settings.Providers[i])
+		if err != nil {
+			panic(err) // this should already had been checked
+		}
+	}
 
 	ipVersion := "ipv4"
-	if *userSettings.IPv6 {
+	if *settings.IPv6 {
 		ipVersion = "ipv6"
 	}
 
 	var dialer server.Dialer
-	switch userSettings.UpstreamType {
+	switch settings.UpstreamType {
-	case settings.DNSUpstreamTypeDot:
+	case "dot":
 		dialerSettings := dot.Settings{
 			UpstreamResolvers: upstreamResolvers,
 			IPVersion:         ipVersion,
@@ -51,7 +56,7 @@ func buildServerSettings(userSettings settings.DNS,
 		if err != nil {
 			return server.Settings{}, fmt.Errorf("creating DNS over TLS dialer: %w", err)
 		}
-	case settings.DNSUpstreamTypeDoh:
+	case "doh":
 		dialerSettings := doh.Settings{
 			UpstreamResolvers: upstreamResolvers,
 			IPVersion:         ipVersion,
@@ -60,7 +65,7 @@ func buildServerSettings(userSettings settings.DNS,
 		if err != nil {
 			return server.Settings{}, fmt.Errorf("creating DNS over HTTPS dialer: %w", err)
 		}
-	case settings.DNSUpstreamTypePlain:
+	case "plain":
 		dialerSettings := plain.Settings{
 			UpstreamResolvers: upstreamResolvers,
 			IPVersion:         ipVersion,
@@ -70,11 +75,11 @@ func buildServerSettings(userSettings settings.DNS,
 			return server.Settings{}, fmt.Errorf("creating plain DNS dialer: %w", err)
 		}
 	default:
-		panic("unknown upstream type: " + userSettings.UpstreamType)
+		panic("unknown upstream type: " + settings.UpstreamType)
 	}
 	serverSettings.Dialer = dialer
 
-	if *userSettings.Caching {
+	if *settings.Caching {
 		lruCache, err := lru.New(lru.Settings{})
 		if err != nil {
 			return server.Settings{}, fmt.Errorf("creating LRU cache: %w", err)
@@ -96,67 +101,5 @@ func buildServerSettings(userSettings settings.DNS,
 	}
 	serverSettings.Middlewares = append(serverSettings.Middlewares, filterMiddleware)
 
-	localResolversAddrPorts := make([]netip.AddrPort, len(localResolvers))
-	const defaultDNSPort = 53
-	for i, addr := range localResolvers {
-		localResolversAddrPorts[i] = netip.AddrPortFrom(addr, defaultDNSPort)
-	}
-	localDNSMiddleware, err := localdns.New(localdns.Settings{
-		Resolvers: localResolversAddrPorts, // auto-detected at container start only
-		Logger:    logger,
-	})
-	if err != nil {
-		return server.Settings{}, fmt.Errorf("creating local DNS middleware: %w", err)
-	}
-	// Place after cache middleware, since we want to avoid caching for local
-	// hostnames that may change regularly.
-	// Place after filter middleware to avoid conflicts with the rebinding protection.
-	serverSettings.Middlewares = append(serverSettings.Middlewares, localDNSMiddleware)
-
 	return serverSettings, nil
 }
-
-func buildProviders(userSettings settings.DNS) []provider.Provider {
-	if userSettings.UpstreamType == settings.DNSUpstreamTypePlain &&
-		len(userSettings.UpstreamPlainAddresses) > 0 {
-		providers := make([]provider.Provider, len(userSettings.UpstreamPlainAddresses))
-		for i, addrPort := range userSettings.UpstreamPlainAddresses {
-			providers[i] = provider.Provider{
-				Name: addrPort.String(),
-			}
-			if addrPort.Addr().Is4() {
-				providers[i].Plain.IPv4 = []netip.AddrPort{addrPort}
-			} else {
-				providers[i].Plain.IPv6 = []netip.AddrPort{addrPort}
-			}
-		}
-	}
-
-	providersData := provider.NewProviders()
-	providers := make([]provider.Provider, 0, len(userSettings.Providers)+len(userSettings.UpstreamPlainAddresses))
-	for _, providerName := range userSettings.Providers {
-		provider, err := providersData.Get(providerName)
-		if err != nil {
-			panic(err) // this should already had been checked
-		}
-		providers = append(providers, provider)
-	}
-
-	if userSettings.UpstreamType != settings.DNSUpstreamTypePlain {
-		return providers
-	}
-
-	for _, addrPort := range userSettings.UpstreamPlainAddresses {
-		newProvider := provider.Provider{
-			Name: addrPort.String(),
-		}
-		if addrPort.Addr().Is4() {
-			newProvider.Plain.IPv4 = []netip.AddrPort{addrPort}
-		} else {
-			newProvider.Plain.IPv6 = []netip.AddrPort{addrPort}
-		}
-		providers = append(providers, newProvider)
-	}
-
-	return providers
-}

internal/dns/setup.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/netip"
 
 	"github.com/qdm12/dns/v2/pkg/check"
 	"github.com/qdm12/dns/v2/pkg/nameserver"
@@ -20,7 +21,7 @@ func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err erro
 
 	settings := l.GetSettings()
 
-	serverSettings, err := buildServerSettings(settings, l.filter, l.localResolvers, l.logger)
+	serverSettings, err := buildServerSettings(settings, l.filter, l.logger)
 	if err != nil {
 		return nil, fmt.Errorf("building server settings: %w", err)
 	}
@@ -37,8 +38,12 @@ func (l *Loop) setupServer(ctx context.Context) (runError <-chan error, err erro
 	l.server = server
 
 	// use internal DNS server
-	nameserver.UseDNSInternally(nameserver.SettingsInternalDNS{})
+	const defaultDNSPort = 53
+	nameserver.UseDNSInternally(nameserver.SettingsInternalDNS{
+		AddrPort: netip.AddrPortFrom(settings.ServerAddress, defaultDNSPort),
+	})
 	err = nameserver.UseDNSSystemWide(nameserver.SettingsSystemDNS{
+		IPs:        []netip.Addr{settings.ServerAddress},
 		ResolvPath: l.resolvConf,
 	})
 	if err != nil {

internal/dns/state/settings.go

@@ -40,6 +40,8 @@ func (s *State) SetSettings(ctx context.Context, settings settings.DNS) (
 
 	// Restart
 	_, _ = s.statusApplier.ApplyStatus(ctx, constants.Stopped)
-	outcome, _ = s.statusApplier.ApplyStatus(ctx, constants.Running)
+	if *settings.ServerEnabled {
+		outcome, _ = s.statusApplier.ApplyStatus(ctx, constants.Running)
+	}
 	return outcome
 }

internal/dns/update.go

@@ -37,7 +37,6 @@ func (l *Loop) updateFiles(ctx context.Context) (err error) {
 		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/healthcheck/checker.go

@@ -131,18 +131,9 @@ func (c *Checker) smallPeriodicCheck(ctx context.Context) error {
 	c.configMutex.Lock()
 	ip := c.icmpTarget
 	c.configMutex.Unlock()
-	tryTimeouts := []time.Duration{
+	const maxTries = 3
-		5 * time.Second,
+	const timeout = 10 * time.Second
-		5 * time.Second,
+	const extraTryTime = 10 * time.Second // 10s added for each subsequent retry
-		5 * time.Second,
-		10 * time.Second,
-		10 * time.Second,
-		10 * time.Second,
-		15 * time.Second,
-		15 * time.Second,
-		15 * time.Second,
-		30 * time.Second,
-	}
 	check := func(ctx context.Context) error {
 		if c.icmpNotPermitted {
 			return c.dnsClient.Check(ctx)
@@ -156,17 +147,19 @@ func (c *Checker) smallPeriodicCheck(ctx context.Context) error {
 		}
 		return err
 	}
-	return withRetries(ctx, tryTimeouts, c.logger, c.smallCheckName, check)
+	return withRetries(ctx, maxTries, timeout, extraTryTime, c.logger, c.smallCheckName, check)
 }
 
 func (c *Checker) fullPeriodicCheck(ctx context.Context) error {
+	const maxTries = 2
 	// 20s timeout in case the connection is under stress
 	// See https://github.com/qdm12/gluetun/issues/2270
-	tryTimeouts := []time.Duration{10 * time.Second, 15 * time.Second, 30 * time.Second}
+	const timeout = 20 * time.Second
+	const extraTryTime = 10 * time.Second // 10s added for each subsequent retry
 	check := func(ctx context.Context) error {
 		return tcpTLSCheck(ctx, c.dialer, c.tlsDialAddr)
 	}
-	return withRetries(ctx, tryTimeouts, c.logger, "TCP+TLS dial", check)
+	return withRetries(ctx, maxTries, timeout, extraTryTime, c.logger, "TCP+TLS dial", check)
 }
 
 func tcpTLSCheck(ctx context.Context, dialer *net.Dialer, targetAddress string) error {
@@ -225,17 +218,13 @@ func makeAddressToDial(address string) (addressToDial string, err error) {
 
 var ErrAllCheckTriesFailed = errors.New("all check tries failed")
 
-func withRetries(ctx context.Context, tryTimeouts []time.Duration,
+func withRetries(ctx context.Context, maxTries uint, tryTimeout, extraTryTime time.Duration,
 	logger Logger, checkName string, check func(ctx context.Context) error,
 ) error {
-	maxTries := len(tryTimeouts)
+	try := uint(0)
-	type errData struct {
+	var errs []error
-		err      error
+	for {
-		duration time.Duration
+		timeout := tryTimeout + time.Duration(try)*extraTryTime //nolint:gosec
-	}
-	errs := make([]errData, maxTries)
-	for i, timeout := range tryTimeouts {
-		start := time.Now()
 		checkCtx, cancel := context.WithTimeout(ctx, timeout)
 		err := check(checkCtx)
 		cancel()
@@ -245,14 +234,17 @@ func withRetries(ctx context.Context, tryTimeouts []time.Duration,
 		case ctx.Err() != nil:
 			return fmt.Errorf("%s: %w", checkName, ctx.Err())
 		}
-		logger.Debugf("%s attempt %d/%d failed: %s", checkName, i+1, maxTries, err)
+		logger.Debugf("%s attempt %d/%d failed: %s", checkName, try+1, maxTries, err)
-		errs[i].err = err
+		errs = append(errs, err)
-		errs[i].duration = time.Since(start)
+		try++
+		if try < maxTries {
+			continue
+		}
+		errStrings := make([]string, len(errs))
+		for i, err := range errs {
+			errStrings[i] = fmt.Sprintf("attempt %d: %s", i+1, err.Error())
+		}
+		return fmt.Errorf("%w: after %d %s attempts (%s)",
+			ErrAllCheckTriesFailed, maxTries, checkName, strings.Join(errStrings, "; "))
 	}
-
-	errStrings := make([]string, len(errs))
-	for i, err := range errs {
-		errStrings[i] = fmt.Sprintf("attempt %d (%s): %s", i+1, err.duration, err.err)
-	}
-	return fmt.Errorf("%w: %s", ErrAllCheckTriesFailed, strings.Join(errStrings, ", "))
 }

internal/healthcheck/dns/dns.go

@@ -44,12 +44,12 @@ func concatAddrPorts(addrs [][]netip.AddrPort) []netip.AddrPort {
 var ErrLookupNoIPs = errors.New("no IPs found from DNS lookup")
 
 func (c *Client) Check(ctx context.Context) error {
-	dnsAddr := c.serverAddrs[c.dnsIPIndex].String()
+	dnsAddr := c.serverAddrs[c.dnsIPIndex].Addr()
 	resolver := &net.Resolver{
 		PreferGo: true,
 		Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
 			dialer := net.Dialer{}
-			return dialer.DialContext(ctx, "udp", dnsAddr)
+			return dialer.DialContext(ctx, "udp", dnsAddr.String())
 		},
 	}
 	ips, err := resolver.LookupIP(ctx, "ip", "github.com")

internal/healthcheck/run.go

@@ -10,13 +10,11 @@ import (
 func (s *Server) Run(ctx context.Context, done chan<- struct{}) {
 	defer close(done)
 
-	const readHeaderTimeout = 100 * time.Millisecond
-	const readTimeout = 500 * time.Millisecond
 	server := http.Server{
 		Addr:              s.config.ServerAddress,
 		Handler:           s.handler,
-		ReadHeaderTimeout: readHeaderTimeout,
+		ReadHeaderTimeout: s.config.ReadHeaderTimeout,
-		ReadTimeout:       readTimeout,
+		ReadTimeout:       s.config.ReadTimeout,
 	}
 	serverDone := make(chan struct{})
 	go func() {

internal/netlink/link.go

@@ -62,6 +62,10 @@ func (n *NetLink) LinkSetDown(link Link) (err error) {
 	return netlink.LinkSetDown(linkToNetlinkLink(&link))
 }
 
+func (n *NetLink) LinkSetMTU(link Link, mtu int) error {
+	return netlink.LinkSetMTU(linkToNetlinkLink(&link), mtu)
+}
+
 type netlinkLinkImpl struct {
 	attrs    *netlink.LinkAttrs
 	linkType string

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 int) (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 +1,12 @@
+//go:build linux
+
+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     = 68
+	icmpv4Protocol = 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 int, pingTimeout time.Duration, logger Logger,
+) (mtu int, 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 = int(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 int, pingTimeout time.Duration, logger Logger,
+) (mtu int, 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 = typedBody.MTU
+			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 typedBody.MTU, nil
+		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 int) (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 int
+	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 int, pingTimeout time.Duration, logger Logger) (
+	mtu int, 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       int
+	echoID    uint16
+	sentBytes int
+	ok        bool
+}
+
+func pmtudMultiSizes(ctx context.Context, ip netip.Addr,
+	minMTU, maxPossibleMTU int, pingTimeout time.Duration,
+	logger Logger,
+) (maxMTU int, 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 int) (mtus []int) {
+	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([]int, 0, diff)
+		for mtu := minMTU; mtu <= maxMTU; mtu++ {
+			mtus = append(mtus, mtu)
+		}
+	default:
+		step := float64(diff) / float64(mtusLength-1)
+		mtus = make([]int, 0, mtusLength)
+		for mtu := float64(minMTU); len(mtus) < mtusLength-1; mtu += step {
+			mtus = append(mtus, int(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 int
+		maxMTU int
+		mtus   []int
+	}{
+		"0_0": {
+			mtus: []int{0},
+		},
+		"0_1": {
+			maxMTU: 1,
+			mtus:   []int{0, 1},
+		},
+		"0_8": {
+			maxMTU: 8,
+			mtus:   []int{0, 1, 2, 3, 4, 5, 6, 7, 8},
+		},
+		"0_12": {
+			maxMTU: 12,
+			mtus:   []int{0, 1, 2, 4, 5, 6, 7, 8, 10, 11, 12},
+		},
+		"0_80": {
+			maxMTU: 80,
+			mtus:   []int{0, 8, 16, 24, 32, 40, 48, 56, 64, 72, 80},
+		},
+		"0_100": {
+			maxMTU: 100,
+			mtus:   []int{0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100},
+		},
+		"1280_1500": {
+			minMTU: 1280,
+			maxMTU: 1500,
+			mtus:   []int{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/service/command.go

@@ -18,7 +18,6 @@ func runCommand(ctx context.Context, cmder Cmder, logger Logger,
 	}
 	portsString := strings.Join(portStrings, ",")
 	commandString := strings.ReplaceAll(commandTemplate, "{{PORTS}}", portsString)
-	commandString = strings.ReplaceAll(commandString, "{{PORT}}", portStrings[0])
 	args, err := command.Split(commandString)
 	if err != nil {
 		return fmt.Errorf("parsing command: %w", err)

internal/portforward/service/fs.go

@@ -14,11 +14,7 @@ func (s *Service) writePortForwardedFile(ports []uint16) (err error) {
 	fileData := []byte(strings.Join(portStrings, "\n"))
 
 	filepath := s.settings.Filepath
-	if len(ports) == 0 {
+	s.logger.Info("writing port file " + filepath)
-		s.logger.Info("clearing port file " + filepath)
-	} else {
-		s.logger.Info("writing port file " + filepath)
-	}
 	const perms = os.FileMode(0o644)
 	err = os.WriteFile(filepath, fileData, perms)
 	if err != nil {

internal/portforward/service/stop.go

@@ -59,6 +59,8 @@ func (s *Service) cleanup() (err error) {
 
 	s.ports = nil
 
+	filepath := s.settings.Filepath
+	s.logger.Info("clearing port file " + filepath)
 	err = s.writePortForwardedFile(nil)
 	if err != nil {
 		return fmt.Errorf("clearing port file: %w", err)

internal/provider/common/updater.go

@@ -13,7 +13,6 @@ var (
 	ErrNotEnoughServers     = errors.New("not enough servers found")
 	ErrHTTPStatusCodeNotOK  = errors.New("HTTP status code not OK")
 	ErrIPFetcherUnsupported = errors.New("IP fetcher not supported")
-	ErrCredentialsMissing   = errors.New("credentials missing")
 )
 
 type Fetcher interface {

internal/provider/protonvpn/provider.go

@@ -18,12 +18,11 @@ type Provider struct {
 
 func New(storage common.Storage, randSource rand.Source,
 	client *http.Client, updaterWarner common.Warner,
-	username, password string,
 ) *Provider {
 	return &Provider{
 		storage:    storage,
 		randSource: randSource,
-		Fetcher:    updater.New(client, updaterWarner, username, password),
+		Fetcher:    updater.New(client, updaterWarner),
 	}
 }
 

internal/provider/protonvpn/updater/api.go

@@ -1,567 +1,15 @@
 package updater
 
 import (
-	"bytes"
 	"context"
-	crand "crypto/rand"
-	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
-	"math/rand/v2"
 	"net/http"
 	"net/netip"
-	"slices"
-	"strings"
-
-	srp "github.com/ProtonMail/go-srp"
 )
 
-// apiClient is a minimal Proton v4 API client which can handle all the
+var ErrHTTPStatusCodeNotOK = errors.New("HTTP status code not OK")
-// oddities of Proton's authentication flow they want to keep hidden
-// from the public.
-type apiClient struct {
-	apiURLBase string
-	httpClient *http.Client
-	appVersion string
-	userAgent  string
-	generator  *rand.ChaCha8
-}
-
-// newAPIClient returns an [apiClient] with sane defaults matching Proton's
-// insane expectations.
-func newAPIClient(ctx context.Context, httpClient *http.Client) (client *apiClient, err error) {
-	var seed [32]byte
-	_, _ = crand.Read(seed[:])
-	generator := rand.NewChaCha8(seed)
-
-	// Pick a random user agent from this list. Because I'm not going to tell
-	// Proton shit on where all these funny requests are coming from, given their
-	// unhelpfulness in figuring out their authentication flow.
-	userAgents := [...]string{
-		"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:143.0) Gecko/20100101 Firefox/143.0",
-		"Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:143.0) Gecko/20100101 Firefox/143.0",
-		"Mozilla/5.0 (X11; Linux x86_64; rv:143.0) Gecko/20100101 Firefox/143.0",
-	}
-	userAgent := userAgents[generator.Uint64()%uint64(len(userAgents))]
-
-	appVersion, err := getMostRecentStableTag(ctx, httpClient)
-	if err != nil {
-		return nil, fmt.Errorf("getting most recent version for proton app: %w", err)
-	}
-
-	return &apiClient{
-		apiURLBase: "https://account.proton.me/api",
-		httpClient: httpClient,
-		appVersion: appVersion,
-		userAgent:  userAgent,
-		generator:  generator,
-	}, nil
-}
-
-var ErrCodeNotSuccess = errors.New("response code is not success")
-
-// setHeaders sets the minimal necessary headers for Proton API requests
-// to succeed without being blocked by their "security" measures.
-// See for example [getMostRecentStableTag] on how the app version must
-// be set to a recent version or they block your request. "SeCuRiTy"...
-func (c *apiClient) setHeaders(request *http.Request, cookie cookie) {
-	request.Header.Set("Cookie", cookie.String())
-	request.Header.Set("User-Agent", c.userAgent)
-	request.Header.Set("x-pm-appversion", c.appVersion)
-	request.Header.Set("x-pm-locale", "en_US")
-	request.Header.Set("x-pm-uid", cookie.uid)
-}
-
-// authenticate performs the full Proton authentication flow
-// to obtain an authenticated cookie (uid, token and session ID).
-func (c *apiClient) authenticate(ctx context.Context, username, password string,
-) (authCookie cookie, err error) {
-	sessionID, err := c.getSessionID(ctx)
-	if err != nil {
-		return cookie{}, fmt.Errorf("getting session ID: %w", err)
-	}
-
-	tokenType, accessToken, refreshToken, uid, err := c.getUnauthSession(ctx, sessionID)
-	if err != nil {
-		return cookie{}, fmt.Errorf("getting unauthenticated session data: %w", err)
-	}
-
-	cookieToken, err := c.cookieToken(ctx, sessionID, tokenType, accessToken, refreshToken, uid)
-	if err != nil {
-		return cookie{}, fmt.Errorf("getting cookie token: %w", err)
-	}
-
-	unauthCookie := cookie{
-		uid:       uid,
-		token:     cookieToken,
-		sessionID: sessionID,
-	}
-	modulusPGPClearSigned, serverEphemeralBase64, saltBase64,
-		srpSessionHex, version, err := c.authInfo(ctx, username, unauthCookie)
-	if err != nil {
-		return cookie{}, fmt.Errorf("getting auth information: %w", err)
-	}
-
-	// Prepare SRP proof generator using Proton's official SRP parameters and hashing.
-	srpAuth, err := srp.NewAuth(version, username, []byte(password),
-		saltBase64, modulusPGPClearSigned, serverEphemeralBase64)
-	if err != nil {
-		return cookie{}, fmt.Errorf("initializing SRP auth: %w", err)
-	}
-
-	// Generate SRP proofs (A, M1) with the usual 2048-bit modulus.
-	const modulusBits = 2048
-	proofs, err := srpAuth.GenerateProofs(modulusBits)
-	if err != nil {
-		return cookie{}, fmt.Errorf("generating SRP proofs: %w", err)
-	}
-
-	authCookie, err = c.auth(ctx, unauthCookie, username, srpSessionHex, proofs)
-	if err != nil {
-		return cookie{}, fmt.Errorf("authentifying: %w", err)
-	}
-
-	return authCookie, nil
-}
-
-var ErrSessionIDNotFound = errors.New("session ID not found in cookies")
-
-func (c *apiClient) getSessionID(ctx context.Context) (sessionID string, err error) {
-	const url = "https://account.proton.me/vpn"
-	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
-	if err != nil {
-		return "", fmt.Errorf("creating request: %w", err)
-	}
-
-	response, err := c.httpClient.Do(request)
-	if err != nil {
-		return "", err
-	}
-	err = response.Body.Close()
-	if err != nil {
-		return "", fmt.Errorf("closing response body: %w", err)
-	}
-
-	for _, cookie := range response.Cookies() {
-		if cookie.Name == "Session-Id" {
-			return cookie.Value, nil
-		}
-	}
-
-	return "", fmt.Errorf("%w", ErrSessionIDNotFound)
-}
-
-var ErrDataFieldMissing = errors.New("data field missing in response")
-
-func (c *apiClient) getUnauthSession(ctx context.Context, sessionID string) (
-	tokenType, accessToken, refreshToken, uid string, err error,
-) {
-	request, err := http.NewRequestWithContext(ctx, http.MethodPost, c.apiURLBase+"/auth/v4/sessions", nil)
-	if err != nil {
-		return "", "", "", "", fmt.Errorf("creating request: %w", err)
-	}
-	unauthCookie := cookie{
-		sessionID: sessionID,
-	}
-	c.setHeaders(request, unauthCookie)
-
-	response, err := c.httpClient.Do(request)
-	if err != nil {
-		return "", "", "", "", err
-	}
-	defer response.Body.Close()
-
-	responseBody, err := io.ReadAll(response.Body)
-	if err != nil {
-		return "", "", "", "", fmt.Errorf("reading response body: %w", err)
-	} else if response.StatusCode != http.StatusOK {
-		return "", "", "", "", buildError(response.StatusCode, responseBody)
-	}
-
-	var data struct {
-		Code         uint     `json:"Code"`         // 1000 on success
-		AccessToken  string   `json:"AccessToken"`  // 32-chars lowercase and digits
-		RefreshToken string   `json:"RefreshToken"` // 32-chars lowercase and digits
-		TokenType    string   `json:"TokenType"`    // "Bearer"
-		Scopes       []string `json:"Scopes"`       // should be [] for our usage
-		UID          string   `json:"UID"`          // 32-chars lowercase and digits
-		LocalID      uint     `json:"LocalID"`      // 0 in my case
-	}
-
-	err = json.Unmarshal(responseBody, &data)
-	if err != nil {
-		return "", "", "", "", fmt.Errorf("decoding response body: %w", err)
-	}
-
-	const successCode = 1000
-	switch {
-	case data.Code != successCode:
-		return "", "", "", "", fmt.Errorf("%w: expected %d got %d",
-			ErrCodeNotSuccess, successCode, data.Code)
-	case data.AccessToken == "":
-		return "", "", "", "", fmt.Errorf("%w: access token is empty", ErrDataFieldMissing)
-	case data.RefreshToken == "":
-		return "", "", "", "", fmt.Errorf("%w: refresh token is empty", ErrDataFieldMissing)
-	case data.TokenType == "":
-		return "", "", "", "", fmt.Errorf("%w: token type is empty", ErrDataFieldMissing)
-	case data.UID == "":
-		return "", "", "", "", fmt.Errorf("%w: UID is empty", ErrDataFieldMissing)
-	}
-	// Ignore Scopes and LocalID fields, we don't use them.
-
-	return data.TokenType, data.AccessToken, data.RefreshToken, data.UID, nil
-}
-
-var ErrUIDMismatch = errors.New("UID in response does not match request UID")
-
-func (c *apiClient) cookieToken(ctx context.Context, sessionID, tokenType, accessToken,
-	refreshToken, uid string,
-) (cookieToken string, err error) {
-	type requestBodySchema struct {
-		GrantType    string `json:"GrantType"`    // "refresh_token"
-		Persistent   uint   `json:"Persistent"`   // 0
-		RedirectURI  string `json:"RedirectURI"`  // "https://protonmail.com"
-		RefreshToken string `json:"RefreshToken"` // 32-chars lowercase and digits
-		ResponseType string `json:"ResponseType"` // "token"
-		State        string `json:"State"`        // 24-chars letters and digits
-		UID          string `json:"UID"`          // 32-chars lowercase and digits
-	}
-	requestBody := requestBodySchema{
-		GrantType:    "refresh_token",
-		Persistent:   0,
-		RedirectURI:  "https://protonmail.com",
-		RefreshToken: refreshToken,
-		ResponseType: "token",
-		State:        generateLettersDigits(c.generator, 24), //nolint:mnd
-		UID:          uid,
-	}
-
-	buffer := bytes.NewBuffer(nil)
-	encoder := json.NewEncoder(buffer)
-	if err := encoder.Encode(requestBody); err != nil {
-		return "", fmt.Errorf("encoding request body: %w", err)
-	}
-
-	request, err := http.NewRequestWithContext(ctx, http.MethodPost, c.apiURLBase+"/core/v4/auth/cookies", buffer)
-	if err != nil {
-		return "", fmt.Errorf("creating request: %w", err)
-	}
-	unauthCookie := cookie{
-		uid:       uid,
-		sessionID: sessionID,
-	}
-	c.setHeaders(request, unauthCookie)
-	request.Header.Set("Authorization", tokenType+" "+accessToken)
-
-	response, err := c.httpClient.Do(request)
-	if err != nil {
-		return "", err
-	}
-	defer response.Body.Close()
-
-	responseBody, err := io.ReadAll(response.Body)
-	if err != nil {
-		return "", fmt.Errorf("reading response body: %w", err)
-	} else if response.StatusCode != http.StatusOK {
-		return "", buildError(response.StatusCode, responseBody)
-	}
-
-	var cookies struct {
-		Code           uint   `json:"Code"`           // 1000 on success
-		UID            string `json:"UID"`            // should match request UID
-		LocalID        uint   `json:"LocalID"`        // 0
-		RefreshCounter uint   `json:"RefreshCounter"` // 1
-	}
-	err = json.Unmarshal(responseBody, &cookies)
-	if err != nil {
-		return "", fmt.Errorf("decoding response body: %w", err)
-	}
-
-	const successCode = 1000
-	switch {
-	case cookies.Code != successCode:
-		return "", fmt.Errorf("%w: expected %d got %d",
-			ErrCodeNotSuccess, successCode, cookies.Code)
-	case cookies.UID != requestBody.UID:
-		return "", fmt.Errorf("%w: expected %s got %s",
-			ErrUIDMismatch, requestBody.UID, cookies.UID)
-	}
-	// Ignore LocalID and RefreshCounter fields, we don't use them.
-
-	for _, cookie := range response.Cookies() {
-		if cookie.Name == "AUTH-"+uid {
-			return cookie.Value, nil
-		}
-	}
-
-	return "", fmt.Errorf("%w", ErrAuthCookieNotFound)
-}
-
-var (
-	ErrUsernameDoesNotExist = errors.New("username does not exist")
-	ErrUsernameMismatch     = errors.New("username in response does not match request username")
-)
-
-// authInfo fetches SRP parameters for the account.
-func (c *apiClient) authInfo(ctx context.Context, username string, unauthCookie cookie) (
-	modulusPGPClearSigned, serverEphemeralBase64, saltBase64, srpSessionHex string,
-	version int, err error,
-) {
-	type requestBodySchema struct {
-		Intent   string `json:"Intent"`   // "Proton"
-		Username string `json:"Username"` // username without @domain.com
-	}
-	requestBody := requestBodySchema{
-		Intent:   "Proton",
-		Username: username,
-	}
-
-	buffer := bytes.NewBuffer(nil)
-	encoder := json.NewEncoder(buffer)
-	if err := encoder.Encode(requestBody); err != nil {
-		return "", "", "", "", 0, fmt.Errorf("encoding request body: %w", err)
-	}
-
-	request, err := http.NewRequestWithContext(ctx, http.MethodPost, c.apiURLBase+"/core/v4/auth/info", buffer)
-	if err != nil {
-		return "", "", "", "", 0, fmt.Errorf("creating request: %w", err)
-	}
-	c.setHeaders(request, unauthCookie)
-
-	response, err := c.httpClient.Do(request)
-	if err != nil {
-		return "", "", "", "", 0, err
-	}
-	defer response.Body.Close()
-
-	responseBody, err := io.ReadAll(response.Body)
-	if err != nil {
-		return "", "", "", "", 0, fmt.Errorf("reading response body: %w", err)
-	} else if response.StatusCode != http.StatusOK {
-		return "", "", "", "", 0, buildError(response.StatusCode, responseBody)
-	}
-
-	var info struct {
-		Code            uint   `json:"Code"`              // 1000 on success
-		Modulus         string `json:"Modulus"`           // PGP clearsigned modulus string
-		ServerEphemeral string `json:"ServerEphemeral"`   // base64
-		Version         *uint  `json:"Version,omitempty"` // 4 as of 2025-10-26
-		Salt            string `json:"Salt"`              // base64
-		SRPSession      string `json:"SRPSession"`        // hexadecimal
-		Username        string `json:"Username"`          // user without @domain.com. Mine has its first letter capitalized.
-	}
-	err = json.Unmarshal(responseBody, &info)
-	if err != nil {
-		return "", "", "", "", 0, fmt.Errorf("decoding response body: %w", err)
-	}
-
-	const successCode = 1000
-	switch {
-	case info.Code != successCode:
-		return "", "", "", "", 0, fmt.Errorf("%w: expected %d got %d",
-			ErrCodeNotSuccess, successCode, info.Code)
-	case info.Modulus == "":
-		return "", "", "", "", 0, fmt.Errorf("%w: modulus is empty", ErrDataFieldMissing)
-	case info.ServerEphemeral == "":
-		return "", "", "", "", 0, fmt.Errorf("%w: server ephemeral is empty", ErrDataFieldMissing)
-	case info.Salt == "":
-		return "", "", "", "", 0, fmt.Errorf("%w (salt data field is empty)", ErrUsernameDoesNotExist)
-	case info.SRPSession == "":
-		return "", "", "", "", 0, fmt.Errorf("%w: SRP session is empty", ErrDataFieldMissing)
-
-	case !strings.EqualFold(info.Username, username):
-		return "", "", "", "", 0, fmt.Errorf("%w: expected %s got %s",
-			ErrUsernameMismatch, username, info.Username)
-	case info.Version == nil:
-		return "", "", "", "", 0, fmt.Errorf("%w: version is missing", ErrDataFieldMissing)
-	}
-
-	version = int(*info.Version) //nolint:gosec
-	return info.Modulus, info.ServerEphemeral, info.Salt,
-		info.SRPSession, version, nil
-}
-
-type cookie struct {
-	uid       string
-	token     string
-	sessionID string
-}
-
-func (c *cookie) String() string {
-	s := ""
-	if c.token != "" {
-		s += fmt.Sprintf("AUTH-%s=%s; ", c.uid, c.token)
-	}
-	if c.sessionID != "" {
-		s += fmt.Sprintf("Session-Id=%s; ", c.sessionID)
-	}
-	if c.token != "" {
-		s += "Tag=default; iaas=W10; Domain=proton.me; Feature=VPNDashboard:A"
-	}
-	return s
-}
-
-var (
-	// ErrServerProofNotValid indicates the M2 from the server didn't match the expected proof.
-	ErrServerProofNotValid = errors.New("server proof from server is not valid")
-	ErrVPNScopeNotFound    = errors.New("VPN scope not found in scopes")
-	ErrTwoFANotSupported   = errors.New("two factor authentication not supported in this client")
-	ErrAuthCookieNotFound  = errors.New("auth cookie not found")
-)
-
-// auth performs the SRP proof submission (and optionally TOTP) to obtain tokens.
-func (c *apiClient) auth(ctx context.Context, unauthCookie cookie,
-	username, srpSession string, proofs *srp.Proofs,
-) (authCookie cookie, err error) {
-	clientEphemeral := base64.StdEncoding.EncodeToString(proofs.ClientEphemeral)
-	clientProof := base64.StdEncoding.EncodeToString(proofs.ClientProof)
-
-	type requestBodySchema struct {
-		ClientEphemeral string            `json:"ClientEphemeral"`   // base64(A)
-		ClientProof     string            `json:"ClientProof"`       // base64(M1)
-		Payload         map[string]string `json:"Payload,omitempty"` // not sure
-		SRPSession      string            `json:"SRPSession"`        // hexadecimal
-		Username        string            `json:"Username"`          // user@protonmail.com
-	}
-	requestBody := requestBodySchema{
-		ClientEphemeral: clientEphemeral,
-		ClientProof:     clientProof,
-		SRPSession:      srpSession,
-		Username:        username,
-	}
-
-	buffer := bytes.NewBuffer(nil)
-	encoder := json.NewEncoder(buffer)
-	if err := encoder.Encode(requestBody); err != nil {
-		return cookie{}, fmt.Errorf("encoding request body: %w", err)
-	}
-
-	request, err := http.NewRequestWithContext(ctx, http.MethodPost, c.apiURLBase+"/core/v4/auth", buffer)
-	if err != nil {
-		return cookie{}, fmt.Errorf("creating request: %w", err)
-	}
-	c.setHeaders(request, unauthCookie)
-
-	response, err := c.httpClient.Do(request)
-	if err != nil {
-		return cookie{}, err
-	}
-	defer response.Body.Close()
-
-	responseBody, err := io.ReadAll(response.Body)
-	if err != nil {
-		return cookie{}, fmt.Errorf("reading response body: %w", err)
-	} else if response.StatusCode != http.StatusOK {
-		return cookie{}, buildError(response.StatusCode, responseBody)
-	}
-
-	type twoFAStatus uint
-	//nolint:unused
-	const (
-		twoFADisabled twoFAStatus = iota
-		twoFAHasTOTP
-		twoFAHasFIDO2
-		twoFAHasFIDO2AndTOTP
-	)
-	type twoFAInfo struct {
-		Enabled twoFAStatus `json:"Enabled"`
-		FIDO2   struct {
-			AuthenticationOptions any   `json:"AuthenticationOptions"`
-			RegisteredKeys        []any `json:"RegisteredKeys"`
-		} `json:"FIDO2"`
-		TOTP uint `json:"TOTP"`
-	}
-
-	var auth struct {
-		Code              uint      `json:"Code"`         // 1000 on success
-		LocalID           uint      `json:"LocalID"`      // 7 in my case
-		Scopes            []string  `json:"Scopes"`       // this should contain "vpn". Same as `Scope` field value.
-		UID               string    `json:"UID"`          // same as `Uid` field value
-		UserID            string    `json:"UserID"`       // base64
-		EventID           string    `json:"EventID"`      // base64
-		PasswordMode      uint      `json:"PasswordMode"` // 1 in my case
-		ServerProof       string    `json:"ServerProof"`  // base64(M2)
-		TwoFactor         uint      `json:"TwoFactor"`    // 0 if 2FA not required
-		TwoFA             twoFAInfo `json:"2FA"`
-		TemporaryPassword uint      `json:"TemporaryPassword"` // 0 in my case
-	}
-
-	err = json.Unmarshal(responseBody, &auth)
-	if err != nil {
-		return cookie{}, fmt.Errorf("decoding response body: %w", err)
-	}
-
-	m2, err := base64.StdEncoding.DecodeString(auth.ServerProof)
-	if err != nil {
-		return cookie{}, fmt.Errorf("decoding server proof: %w", err)
-	}
-	if !bytes.Equal(m2, proofs.ExpectedServerProof) {
-		return cookie{}, fmt.Errorf("%w: expected %x got %x",
-			ErrServerProofNotValid, proofs.ExpectedServerProof, m2)
-	}
-
-	const successCode = 1000
-	switch {
-	case auth.Code != successCode:
-		return cookie{}, fmt.Errorf("%w: expected %d got %d",
-			ErrCodeNotSuccess, successCode, auth.Code)
-	case auth.UID != unauthCookie.uid:
-		return cookie{}, fmt.Errorf("%w: expected %s got %s",
-			ErrUIDMismatch, unauthCookie.uid, auth.UID)
-	case auth.TwoFactor != 0:
-		return cookie{}, fmt.Errorf("%w", ErrTwoFANotSupported)
-	case !slices.Contains(auth.Scopes, "vpn"):
-		return cookie{}, fmt.Errorf("%w: in %v", ErrVPNScopeNotFound, auth.Scopes)
-	}
-
-	for _, setCookieHeader := range response.Header.Values("Set-Cookie") {
-		parts := strings.Split(setCookieHeader, ";")
-		for _, part := range parts {
-			if strings.HasPrefix(part, "AUTH-"+unauthCookie.uid+"=") {
-				authCookie = unauthCookie
-				authCookie.token = strings.TrimPrefix(part, "AUTH-"+unauthCookie.uid+"=")
-				return authCookie, nil
-			}
-		}
-	}
-
-	return cookie{}, fmt.Errorf("%w: in HTTP headers %s",
-		ErrAuthCookieNotFound, httpHeadersToString(response.Header))
-}
-
-// generateLettersDigits mimicing Proton's own random string generator:
-// https://github.com/ProtonMail/WebClients/blob/e4d7e4ab9babe15b79a131960185f9f8275512cd/packages/utils/generateLettersDigits.ts
-func generateLettersDigits(rng *rand.ChaCha8, length uint) string {
-	const charset = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
-	return generateFromCharset(rng, length, charset)
-}
-
-func generateFromCharset(rng *rand.ChaCha8, length uint, charset string) string {
-	result := make([]byte, length)
-	randomBytes := make([]byte, length)
-	_, _ = rng.Read(randomBytes)
-	for i := range length {
-		result[i] = charset[int(randomBytes[i])%len(charset)]
-	}
-	return string(result)
-}
-
-func httpHeadersToString(headers http.Header) string {
-	var builder strings.Builder
-	first := true
-	for key, values := range headers {
-		for _, value := range values {
-			if !first {
-				builder.WriteString(", ")
-			}
-			builder.WriteString(fmt.Sprintf("%s: %s", key, value))
-			first = false
-		}
-	}
-	return builder.String()
-}
 
 type apiData struct {
 	LogicalServers []logicalServer `json:"LogicalServers"`
@@ -585,25 +33,25 @@ type physicalServer struct {
 	X25519PublicKey string     `json:"X25519PublicKey"`
 }
 
-func (c *apiClient) fetchServers(ctx context.Context, cookie cookie) (
+func fetchAPI(ctx context.Context, client *http.Client) (
 	data apiData, err error,
 ) {
-	const url = "https://account.proton.me/api/vpn/logicals"
+	const url = "https://api.protonmail.ch/vpn/logicals"
+
 	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
 	if err != nil {
 		return data, err
 	}
-	c.setHeaders(request, cookie)
 
-	response, err := c.httpClient.Do(request)
+	response, err := client.Do(request)
 	if err != nil {
 		return data, err
 	}
 	defer response.Body.Close()
 
 	if response.StatusCode != http.StatusOK {
-		b, _ := io.ReadAll(response.Body)
+		return data, fmt.Errorf("%w: %d %s", ErrHTTPStatusCodeNotOK,
-		return data, buildError(response.StatusCode, b)
+			response.StatusCode, response.Status)
 	}
 
 	decoder := json.NewDecoder(response.Body)
@@ -611,31 +59,9 @@ func (c *apiClient) fetchServers(ctx context.Context, cookie cookie) (
 		return data, fmt.Errorf("decoding response body: %w", err)
 	}
 
+	if err := response.Body.Close(); err != nil {
+		return data, err
+	}
+
 	return data, nil
 }
-
-var ErrHTTPStatusCodeNotOK = errors.New("HTTP status code not OK")
-
-func buildError(httpCode int, body []byte) error {
-	prettyCode := http.StatusText(httpCode)
-	var protonError struct {
-		Code    *int              `json:"Code,omitempty"`
-		Error   *string           `json:"Error,omitempty"`
-		Details map[string]string `json:"Details"`
-	}
-	decoder := json.NewDecoder(bytes.NewReader(body))
-	decoder.DisallowUnknownFields()
-	err := decoder.Decode(&protonError)
-	if err != nil || protonError.Error == nil || protonError.Code == nil {
-		return fmt.Errorf("%w: %s: %s",
-			ErrHTTPStatusCodeNotOK, prettyCode, body)
-	}
-
-	details := make([]string, 0, len(protonError.Details))
-	for key, value := range protonError.Details {
-		details = append(details, fmt.Sprintf("%s: %s", key, value))
-	}
-
-	return fmt.Errorf("%w: %s: %s (code %d with details: %s)",
-		ErrHTTPStatusCodeNotOK, prettyCode, *protonError.Error, *protonError.Code, strings.Join(details, ", "))
-}

internal/provider/protonvpn/updater/servers.go

@@ -13,26 +13,9 @@ import (
 func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 	servers []models.Server, err error,
 ) {
-	switch {
+	data, err := fetchAPI(ctx, u.client)
-	case u.username == "":
-		return nil, fmt.Errorf("%w: username is empty", common.ErrCredentialsMissing)
-	case u.password == "":
-		return nil, fmt.Errorf("%w: password is empty", common.ErrCredentialsMissing)
-	}
-
-	apiClient, err := newAPIClient(ctx, u.client)
 	if err != nil {
-		return nil, fmt.Errorf("creating API client: %w", err)
+		return nil, err
-	}
-
-	cookie, err := apiClient.authenticate(ctx, u.username, u.password)
-	if err != nil {
-		return nil, fmt.Errorf("authentifying with Proton: %w", err)
-	}
-
-	data, err := apiClient.fetchServers(ctx, cookie)
-	if err != nil {
-		return nil, fmt.Errorf("fetching logical servers: %w", err)
 	}
 
 	countryCodes := constants.CountryCodes()

internal/provider/protonvpn/updater/updater.go

@@ -7,17 +7,13 @@ import (
 )
 
 type Updater struct {
-	client   *http.Client
+	client *http.Client
-	username string
+	warner common.Warner
-	password string
-	warner   common.Warner
 }
 
-func New(client *http.Client, warner common.Warner, username, password string) *Updater {
+func New(client *http.Client, warner common.Warner) *Updater {
 	return &Updater{
-		client:   client,
+		client: client,
-		username: username,
+		warner: warner,
-		password: password,
-		warner:   warner,
 	}
 }

internal/provider/protonvpn/updater/version.go

@@ -1,64 +0,0 @@
-package updater
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"net/http"
-	"regexp"
-	"strings"
-)
-
-// getMostRecentStableTag finds the most recent proton-account stable tag version,
-// in order to use it in the x-pm-appversion http request header. Because if we do
-// fall behind on versioning, Proton doesn't like it because they like to create
-// complications where there is no need for it. Hence this function.
-func getMostRecentStableTag(ctx context.Context, client *http.Client) (version string, err error) {
-	page := 1
-	regexVersion := regexp.MustCompile(`^proton-account@(\d+\.\d+\.\d+\.\d+)$`)
-	for ctx.Err() == nil {
-		url := "https://api.github.com/repos/ProtonMail/WebClients/tags?per_page=30&page=" + fmt.Sprint(page)
-
-		request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
-		if err != nil {
-			return "", fmt.Errorf("creating request: %w", err)
-		}
-		request.Header.Set("Accept", "application/vnd.github.v3+json")
-
-		response, err := client.Do(request)
-		if err != nil {
-			return "", err
-		}
-		defer response.Body.Close()
-
-		data, err := io.ReadAll(response.Body)
-		if err != nil {
-			return "", fmt.Errorf("reading response body: %w", err)
-		}
-
-		if response.StatusCode != http.StatusOK {
-			return "", fmt.Errorf("%w: %s: %s", ErrHTTPStatusCodeNotOK, response.Status, data)
-		}
-
-		var tags []struct {
-			Name string `json:"name"`
-		}
-		err = json.Unmarshal(data, &tags)
-		if err != nil {
-			return "", fmt.Errorf("decoding JSON response: %w", err)
-		}
-
-		for _, tag := range tags {
-			if !regexVersion.MatchString(tag.Name) {
-				continue
-			}
-			version := "web-account@" + strings.TrimPrefix(tag.Name, "proton-account@")
-			return version, nil
-		}
-
-		page++
-	}
-
-	return "", fmt.Errorf("%w (queried %d pages)", context.Canceled, page)
-}

internal/provider/providers.go

@@ -54,7 +54,7 @@ type Extractor interface {
 func NewProviders(storage Storage, timeNow func() time.Time,
 	updaterWarner common.Warner, client *http.Client, unzipper common.Unzipper,
 	parallelResolver common.ParallelResolver, ipFetcher common.IPFetcher,
-	extractor custom.Extractor, credentials settings.Updater,
+	extractor custom.Extractor,
 ) *Providers {
 	randSource := rand.NewSource(timeNow().UnixNano())
 
@@ -75,7 +75,7 @@ func NewProviders(storage Storage, timeNow func() time.Time,
 		providers.Privado:               privado.New(storage, randSource, ipFetcher, unzipper, updaterWarner, parallelResolver),
 		providers.PrivateInternetAccess: privateinternetaccess.New(storage, randSource, timeNow, client),
 		providers.Privatevpn:            privatevpn.New(storage, randSource, unzipper, updaterWarner, parallelResolver),
-		providers.Protonvpn:             protonvpn.New(storage, randSource, client, updaterWarner, *credentials.ProtonUsername, *credentials.ProtonPassword),
+		providers.Protonvpn:             protonvpn.New(storage, randSource, client, updaterWarner),
 		providers.Purevpn:               purevpn.New(storage, randSource, ipFetcher, unzipper, updaterWarner, parallelResolver),
 		providers.SlickVPN:              slickvpn.New(storage, randSource, client, updaterWarner, parallelResolver),
 		providers.Surfshark:             surfshark.New(storage, randSource, client, unzipper, updaterWarner, parallelResolver),

internal/server/handler.go

@@ -25,14 +25,13 @@ func newHandler(ctx context.Context, logger Logger, logging bool,
 	handler := &handler{}
 
 	vpn := newVPNHandler(ctx, vpnLooper, storage, ipv6Supported, logger)
-	openvpn := newOpenvpnHandler(ctx, vpnLooper, logger)
+	openvpn := newOpenvpnHandler(ctx, vpnLooper, pfGetter, logger)
 	dns := newDNSHandler(ctx, dnsLooper, logger)
 	updater := newUpdaterHandler(ctx, updaterLooper, logger)
 	publicip := newPublicIPHandler(publicIPLooper, logger)
-	portForward := newPortForwardHandler(ctx, pfGetter, logger)
 
 	handler.v0 = newHandlerV0(ctx, logger, vpnLooper, dnsLooper, updaterLooper)
-	handler.v1 = newHandlerV1(logger, buildInfo, vpn, openvpn, dns, updater, publicip, portForward)
+	handler.v1 = newHandlerV1(logger, buildInfo, vpn, openvpn, dns, updater, publicip)
 
 	authMiddleware, err := auth.New(authSettings, logger)
 	if err != nil {

internal/server/handlerv0.go

@@ -52,7 +52,7 @@ func (h *handlerV0) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			h.logger.Warn(err.Error())
 		}
 	case "/openvpn/portforwarded":
-		http.Redirect(w, r, "/v1/portforward", http.StatusPermanentRedirect)
+		http.Redirect(w, r, "/v1/openvpn/portforwarded", http.StatusPermanentRedirect)
 	case "/openvpn/settings":
 		http.Redirect(w, r, "/v1/openvpn/settings", http.StatusPermanentRedirect)
 	case "/updater/restart":

internal/server/handlerv1.go

@@ -10,29 +10,27 @@ import (
 )
 
 func newHandlerV1(w warner, buildInfo models.BuildInformation,
-	vpn, openvpn, dns, updater, publicip, portForward http.Handler,
+	vpn, openvpn, dns, updater, publicip http.Handler,
 ) http.Handler {
 	return &handlerV1{
-		warner:      w,
+		warner:    w,
-		buildInfo:   buildInfo,
+		buildInfo: buildInfo,
-		vpn:         vpn,
+		vpn:       vpn,
-		openvpn:     openvpn,
+		openvpn:   openvpn,
-		dns:         dns,
+		dns:       dns,
-		updater:     updater,
+		updater:   updater,
-		publicip:    publicip,
+		publicip:  publicip,
-		portForward: portForward,
 	}
 }
 
 type handlerV1 struct {
-	warner      warner
+	warner    warner
-	buildInfo   models.BuildInformation
+	buildInfo models.BuildInformation
-	vpn         http.Handler
+	vpn       http.Handler
-	openvpn     http.Handler
+	openvpn   http.Handler
-	dns         http.Handler
+	dns       http.Handler
-	updater     http.Handler
+	updater   http.Handler
-	publicip    http.Handler
+	publicip  http.Handler
-	portForward http.Handler
 }
 
 func (h *handlerV1) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -49,8 +47,6 @@ func (h *handlerV1) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		h.updater.ServeHTTP(w, r)
 	case strings.HasPrefix(r.RequestURI, "/publicip"):
 		h.publicip.ServeHTTP(w, r)
-	case strings.HasPrefix(r.RequestURI, "/portforward"):
-		h.portForward.ServeHTTP(w, r)
 	default:
 		errString := fmt.Sprintf("%s %s not found", r.Method, r.RequestURI)
 		http.Error(w, errString, http.StatusBadRequest)

internal/server/middlewares/auth/middleware.go

@@ -20,7 +20,6 @@ func New(settings Settings, debugLogger DebugLogger) (
 			routeToRoles: routeToRoles,
 			unprotectedRoutes: map[string]struct{}{
 				http.MethodGet + " /openvpn/actions/restart": {},
-				http.MethodGet + " /openvpn/portforwarded":   {},
 				http.MethodGet + " /unbound/actions/restart": {},
 				http.MethodGet + " /updater/restart":         {},
 				http.MethodGet + " /v1/version":              {},
@@ -37,7 +36,6 @@ func New(settings Settings, debugLogger DebugLogger) (
 				http.MethodGet + " /v1/updater/status": {},
 				http.MethodPut + " /v1/updater/status": {},
 				http.MethodGet + " /v1/publicip/ip":    {},
-				http.MethodGet + " /v1/portforward":    {},
 			},
 			logger: debugLogger,
 		}

internal/server/middlewares/auth/settings.go

@@ -1,16 +1,12 @@
 package auth
 
 import (
-	"bytes"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"net/http"
-	"slices"
 
 	"github.com/qdm12/gosettings"
 	"github.com/qdm12/gosettings/validate"
-	"github.com/qdm12/gotree"
 )
 
 type Settings struct {
@@ -19,50 +15,6 @@ type Settings struct {
 	Roles []Role
 }
 
-// SetDefaultRole sets a default role to apply to all routes without a
-// previously user-defined role assigned to. Note the role argument
-// routes are ignored. This should be called BEFORE calling [Settings.SetDefaults].
-func (s *Settings) SetDefaultRole(jsonRole string) error {
-	var role Role
-	decoder := json.NewDecoder(bytes.NewBufferString(jsonRole))
-	decoder.DisallowUnknownFields()
-	err := decoder.Decode(&role)
-	if err != nil {
-		return fmt.Errorf("decoding default role: %w", err)
-	}
-	if role.Auth == "" {
-		return nil // no default role to set
-	}
-	err = role.Validate()
-	if err != nil {
-		return fmt.Errorf("validating default role: %w", err)
-	}
-
-	authenticatedRoutes := make(map[string]struct{}, len(validRoutes))
-	for _, role := range s.Roles {
-		for _, route := range role.Routes {
-			authenticatedRoutes[route] = struct{}{}
-		}
-	}
-
-	if len(authenticatedRoutes) == len(validRoutes) {
-		return nil
-	}
-
-	unauthenticatedRoutes := make([]string, 0, len(validRoutes))
-	for route := range validRoutes {
-		_, authenticated := authenticatedRoutes[route]
-		if !authenticated {
-			unauthenticatedRoutes = append(unauthenticatedRoutes, route)
-		}
-	}
-
-	slices.Sort(unauthenticatedRoutes)
-	role.Routes = unauthenticatedRoutes
-	s.Roles = append(s.Roles, role)
-	return nil
-}
-
 func (s *Settings) SetDefaults() {
 	s.Roles = gosettings.DefaultSlice(s.Roles, []Role{{ // TODO v3.41.0 leave empty
 		Name: "public",
@@ -70,7 +22,6 @@ func (s *Settings) SetDefaults() {
 		Routes: []string{
 			http.MethodGet + " /openvpn/actions/restart",
 			http.MethodGet + " /unbound/actions/restart",
-			http.MethodGet + " /openvpn/portforwarded",
 			http.MethodGet + " /updater/restart",
 			http.MethodGet + " /v1/version",
 			http.MethodGet + " /v1/vpn/status",
@@ -83,14 +34,13 @@ func (s *Settings) SetDefaults() {
 			http.MethodGet + " /v1/updater/status",
 			http.MethodPut + " /v1/updater/status",
 			http.MethodGet + " /v1/publicip/ip",
-			http.MethodGet + " /v1/portforward",
 		},
 	}})
 }
 
 func (s Settings) Validate() (err error) {
 	for i, role := range s.Roles {
-		err = role.Validate()
+		err = role.validate()
 		if err != nil {
 			return fmt.Errorf("role %s (%d of %d): %w",
 				role.Name, i+1, len(s.Roles), err)
@@ -111,18 +61,18 @@ const (
 type Role struct {
 	// Name is the role name and is only used for documentation
 	// and in the authentication middleware debug logs.
-	Name string `json:"name"`
+	Name string
-	// Auth is the authentication method to use, which can be 'none', 'basic' or 'apikey'.
+	// Auth is the authentication method to use, which can be 'none' or 'apikey'.
-	Auth string `json:"auth"`
+	Auth string
 	// APIKey is the API key to use when using the 'apikey' authentication.
-	APIKey string `json:"apikey"`
+	APIKey string
 	// Username for HTTP Basic authentication method.
-	Username string `json:"username"`
+	Username string
 	// Password for HTTP Basic authentication method.
-	Password string `json:"password"`
+	Password string
 	// Routes is a list of routes that the role can access in the format
 	// "HTTP_METHOD PATH", for example "GET /v1/vpn/status"
-	Routes []string `json:"-"`
+	Routes []string
 }
 
 var (
@@ -133,7 +83,7 @@ var (
 	ErrRouteNotSupported  = errors.New("route not supported by the control server")
 )
 
-func (r Role) Validate() (err error) {
+func (r Role) validate() (err error) {
 	err = validate.IsOneOf(r.Auth, AuthNone, AuthAPIKey, AuthBasic)
 	if err != nil {
 		return fmt.Errorf("%w: %s", ErrMethodNotSupported, r.Auth)
@@ -162,8 +112,6 @@ func (r Role) Validate() (err error) {
 // WARNING: do not mutate programmatically.
 var validRoutes = map[string]struct{}{ //nolint:gochecknoglobals
 	http.MethodGet + " /openvpn/actions/restart":  {},
-	http.MethodGet + " /openvpn/portforwarded":    {},
-	http.MethodGet + " /openvpn/settings":         {},
 	http.MethodGet + " /unbound/actions/restart":  {},
 	http.MethodGet + " /updater/restart":          {},
 	http.MethodGet + " /v1/version":               {},
@@ -180,22 +128,4 @@ var validRoutes = map[string]struct{}{ //nolint:gochecknoglobals
 	http.MethodGet + " /v1/updater/status":        {},
 	http.MethodPut + " /v1/updater/status":        {},
 	http.MethodGet + " /v1/publicip/ip":           {},
-	http.MethodGet + " /v1/portforward":           {},
-}
-
-func (r Role) ToLinesNode() (node *gotree.Node) {
-	node = gotree.New("Role " + r.Name)
-	node.Appendf("Authentication method: %s", r.Auth)
-	switch r.Auth {
-	case AuthNone:
-	case AuthBasic:
-		node.Appendf("Username: %s", r.Username)
-		node.Appendf("Password: %s", gosettings.ObfuscateKey(r.Password))
-	case AuthAPIKey:
-		node.Appendf("API key: %s", gosettings.ObfuscateKey(r.APIKey))
-	default:
-		panic("missing code for authentication method: " + r.Auth)
-	}
-	node.Appendf("Number of routes covered: %d", len(r.Routes))
-	return node
 }

internal/server/middlewares/log/middleware.go

@@ -38,7 +38,7 @@ func (m *logMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	m.childHandler.ServeHTTP(statefulWriter, r)
 	duration := m.timeNow().Sub(tStart)
 	m.logger.Info(strconv.Itoa(statefulWriter.statusCode) + " " +
-		r.Method + " " + r.URL.String() +
+		r.Method + " " + r.RequestURI +
 		" wrote " + strconv.Itoa(statefulWriter.length) + "B to " +
 		r.RemoteAddr + " in " + duration.String())
 }

internal/server/openvpn.go

@@ -10,10 +10,13 @@ import (
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 )
 
-func newOpenvpnHandler(ctx context.Context, looper VPNLooper, w warner) http.Handler {
+func newOpenvpnHandler(ctx context.Context, looper VPNLooper,
+	pfGetter PortForwardedGetter, w warner,
+) http.Handler {
 	return &openvpnHandler{
 		ctx:    ctx,
 		looper: looper,
+		pf:     pfGetter,
 		warner: w,
 	}
 }
@@ -21,6 +24,7 @@ func newOpenvpnHandler(ctx context.Context, looper VPNLooper, w warner) http.Han
 type openvpnHandler struct {
 	ctx    context.Context //nolint:containedctx
 	looper VPNLooper
+	pf     PortForwardedGetter
 	warner warner
 }
 
@@ -43,10 +47,10 @@ func (h *openvpnHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		default:
 			errMethodNotSupported(w, r.Method)
 		}
-	case "/portforwarded": // TODO v4 remove
+	case "/portforwarded":
 		switch r.Method {
 		case http.MethodGet:
-			http.Redirect(w, r, "/v1/portforward", http.StatusMovedPermanently)
+			h.getPortForwarded(w)
 		default:
 			errMethodNotSupported(w, r.Method)
 		}
@@ -118,3 +122,23 @@ func (h *openvpnHandler) getSettings(w http.ResponseWriter) {
 		return
 	}
 }
+
+func (h *openvpnHandler) getPortForwarded(w http.ResponseWriter) {
+	ports := h.pf.GetPortsForwarded()
+	encoder := json.NewEncoder(w)
+	var data any
+	switch len(ports) {
+	case 0:
+		data = portWrapper{Port: 0} // TODO v4 change to portsWrapper
+	case 1:
+		data = portWrapper{Port: ports[0]} // TODO v4 change to portsWrapper
+	default:
+		data = portsWrapper{Ports: ports}
+	}
+
+	err := encoder.Encode(data)
+	if err != nil {
+		h.warner.Warn(err.Error())
+		w.WriteHeader(http.StatusInternalServerError)
+	}
+}

internal/server/portforward.go

@@ -1,52 +0,0 @@
-package server
-
-import (
-	"context"
-	"encoding/json"
-	"net/http"
-)
-
-func newPortForwardHandler(ctx context.Context,
-	portForward PortForwardedGetter, warner warner,
-) http.Handler {
-	return &portForwardHandler{
-		ctx:         ctx,
-		portForward: portForward,
-		warner:      warner,
-	}
-}
-
-type portForwardHandler struct {
-	ctx         context.Context //nolint:containedctx
-	portForward PortForwardedGetter
-	warner      warner
-}
-
-func (h *portForwardHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	switch r.Method {
-	case http.MethodGet:
-		h.getPortForwarded(w)
-	default:
-		errMethodNotSupported(w, r.Method)
-	}
-}
-
-func (h *portForwardHandler) getPortForwarded(w http.ResponseWriter) {
-	ports := h.portForward.GetPortsForwarded()
-	encoder := json.NewEncoder(w)
-	var data any
-	switch len(ports) {
-	case 0:
-		data = portWrapper{Port: 0} // TODO v4 change to portsWrapper
-	case 1:
-		data = portWrapper{Port: ports[0]} // TODO v4 change to portsWrapper
-	default:
-		data = portsWrapper{Ports: ports}
-	}
-
-	err := encoder.Encode(data)
-	if err != nil {
-		h.warner.Warn(err.Error())
-		w.WriteHeader(http.StatusInternalServerError)
-	}
-}

internal/server/server.go

@@ -6,25 +6,33 @@ import (
 	"fmt"
 	"os"
 
-	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/httpserver"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/server/middlewares/auth"
 )
 
-func New(ctx context.Context, settings settings.ControlServer, logger Logger,
+func New(ctx context.Context, address string, logEnabled bool, logger Logger,
-	buildInfo models.BuildInformation, openvpnLooper VPNLooper,
+	authConfigPath string, buildInfo models.BuildInformation, openvpnLooper VPNLooper,
 	pfGetter PortForwardedGetter, dnsLooper DNSLoop,
 	updaterLooper UpdaterLooper, publicIPLooper PublicIPLoop, storage Storage,
 	ipv6Supported bool) (
 	server *httpserver.Server, err error,
 ) {
-	authSettings, err := setupAuthMiddleware(settings.AuthFilePath, settings.AuthDefaultRole, logger)
+	authSettings, err := auth.Read(authConfigPath)
+	switch {
+	case errors.Is(err, os.ErrNotExist): // no auth file present
+	case err != nil:
+		return nil, fmt.Errorf("reading auth settings: %w", err)
+	default:
+		logger.Infof("read %d roles from authentication file", len(authSettings.Roles))
+	}
+	authSettings.SetDefaults()
+	err = authSettings.Validate()
 	if err != nil {
-		return nil, fmt.Errorf("building authentication middleware settings: %w", err)
+		return nil, fmt.Errorf("validating auth settings: %w", err)
 	}
 
-	handler, err := newHandler(ctx, logger, *settings.Log, authSettings, buildInfo,
+	handler, err := newHandler(ctx, logger, logEnabled, authSettings, buildInfo,
 		openvpnLooper, pfGetter, dnsLooper, updaterLooper, publicIPLooper,
 		storage, ipv6Supported)
 	if err != nil {
@@ -32,7 +40,7 @@ func New(ctx context.Context, settings settings.ControlServer, logger Logger,
 	}
 
 	httpServerSettings := httpserver.Settings{
-		Address: *settings.Address,
+		Address: address,
 		Handler: handler,
 		Logger:  logger,
 	}
@@ -44,26 +52,3 @@ func New(ctx context.Context, settings settings.ControlServer, logger Logger,
 
 	return server, nil
 }
-
-func setupAuthMiddleware(authPath, jsonDefaultRole string, logger Logger) (
-	authSettings auth.Settings, err error,
-) {
-	authSettings, err = auth.Read(authPath)
-	switch {
-	case errors.Is(err, os.ErrNotExist): // no auth file present
-	case err != nil:
-		return auth.Settings{}, fmt.Errorf("reading auth settings: %w", err)
-	default:
-		logger.Infof("read %d roles from authentication file", len(authSettings.Roles))
-	}
-	err = authSettings.SetDefaultRole(jsonDefaultRole)
-	if err != nil {
-		return auth.Settings{}, fmt.Errorf("setting default role: %w", err)
-	}
-	authSettings.SetDefaults()
-	err = authSettings.Validate()
-	if err != nil {
-		return auth.Settings{}, fmt.Errorf("validating auth settings: %w", err)
-	}
-	return authSettings, nil
-}

internal/storage/mocks_generate_test.go

@@ -1,3 +1,3 @@
 package storage
 
-//go:generate mockgen -destination=mocks_test.go -package $GOPACKAGE . Logger
+//go:generate mockgen -destination=mocks_test.go -package $GOPACKAGE . Infoer

internal/storage/mocks_test.go

@@ -1,5 +1,5 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/qdm12/gluetun/internal/storage (interfaces: Logger)
+// Source: github.com/qdm12/gluetun/internal/storage (interfaces: Infoer)
 
 // Package storage is a generated GoMock package.
 package storage
@@ -10,49 +10,37 @@ import (
 	gomock "github.com/golang/mock/gomock"
 )
 
-// MockLogger is a mock of Logger interface.
+// MockInfoer is a mock of Infoer interface.
-type MockLogger struct {
+type MockInfoer struct {
 	ctrl     *gomock.Controller
-	recorder *MockLoggerMockRecorder
+	recorder *MockInfoerMockRecorder
 }
 
-// MockLoggerMockRecorder is the mock recorder for MockLogger.
+// MockInfoerMockRecorder is the mock recorder for MockInfoer.
-type MockLoggerMockRecorder struct {
+type MockInfoerMockRecorder struct {
-	mock *MockLogger
+	mock *MockInfoer
 }
 
-// NewMockLogger creates a new mock instance.
+// NewMockInfoer creates a new mock instance.
-func NewMockLogger(ctrl *gomock.Controller) *MockLogger {
+func NewMockInfoer(ctrl *gomock.Controller) *MockInfoer {
-	mock := &MockLogger{ctrl: ctrl}
+	mock := &MockInfoer{ctrl: ctrl}
-	mock.recorder = &MockLoggerMockRecorder{mock}
+	mock.recorder = &MockInfoerMockRecorder{mock}
 	return mock
 }
 
 // EXPECT returns an object that allows the caller to indicate expected use.
-func (m *MockLogger) EXPECT() *MockLoggerMockRecorder {
+func (m *MockInfoer) EXPECT() *MockInfoerMockRecorder {
 	return m.recorder
 }
 
 // Info mocks base method.
-func (m *MockLogger) Info(arg0 string) {
+func (m *MockInfoer) Info(arg0 string) {
 	m.ctrl.T.Helper()
 	m.ctrl.Call(m, "Info", arg0)
 }
 
 // Info indicates an expected call of Info.
-func (mr *MockLoggerMockRecorder) Info(arg0 interface{}) *gomock.Call {
+func (mr *MockInfoerMockRecorder) Info(arg0 interface{}) *gomock.Call {
 	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Info", reflect.TypeOf((*MockLogger)(nil).Info), arg0)
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Info", reflect.TypeOf((*MockInfoer)(nil).Info), arg0)
-}
-
-// Warn mocks base method.
-func (m *MockLogger) Warn(arg0 string) {
-	m.ctrl.T.Helper()
-	m.ctrl.Call(m, "Warn", arg0)
-}
-
-// Warn indicates an expected call of Warn.
-func (mr *MockLoggerMockRecorder) Warn(arg0 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Warn", reflect.TypeOf((*MockLogger)(nil).Warn), arg0)
 }

internal/storage/read_test.go

@@ -95,7 +95,7 @@ func Test_extractServersFromBytes(t *testing.T) {
 			t.Parallel()
 			ctrl := gomock.NewController(t)
 
-			logger := NewMockLogger(ctrl)
+			logger := NewMockInfoer(ctrl)
 			var previousLogCall *gomock.Call
 			for _, logged := range testCase.logged {
 				call := logger.EXPECT().Info(logged)

internal/storage/storage.go

@@ -13,35 +13,30 @@ type Storage struct {
 	// the embedded JSON file on every call to the
 	// SyncServers method.
 	hardcodedServers models.AllServers
-	logger           Logger
+	logger           Infoer
 	filepath         string
 }
 
-type Logger interface {
+type Infoer interface {
 	Info(s string)
-	Warn(s string)
 }
 
 // New creates a new storage and reads the servers from the
 // embedded servers file and the file on disk.
-// Passing an empty filepath disables the reading and writing of
+// Passing an empty filepath disables writing servers to a file.
-// servers.
+func New(logger Infoer, filepath string) (storage *Storage, err error) {
-func New(logger Logger, filepath string) (storage *Storage, err error) {
 	// A unit test prevents any error from being returned
 	// and ensures all providers are part of the servers returned.
 	hardcodedServers, _ := parseHardcodedServers()
 
 	storage = &Storage{
 		hardcodedServers: hardcodedServers,
-		mergedServers:    hardcodedServers,
 		logger:           logger,
 		filepath:         filepath,
 	}
 
-	if filepath != "" {
+	if err := storage.syncServers(); err != nil {
-		if err := storage.syncServers(); err != nil {
+		return nil, err
-			return nil, err
-		}
 	}
 
 	return storage, nil

internal/storage/sync.go

@@ -46,13 +46,13 @@ func (s *Storage) syncServers() (err error) {
 	}
 
 	// Eventually write file
-	if reflect.DeepEqual(serversOnFile, s.mergedServers) {
+	if s.filepath == "" || reflect.DeepEqual(serversOnFile, s.mergedServers) {
 		return nil
 	}
 
 	err = s.flushToFile(s.filepath)
 	if err != nil {
-		s.logger.Warn("failed writing servers to file: " + err.Error())
+		return fmt.Errorf("writing servers to file: %w", err)
 	}
 	return nil
 }

internal/updater/providers.go

@@ -29,7 +29,7 @@ func (u *Updater) updateProvider(ctx context.Context, provider Provider,
 			u.logger.Warn("note: if running the update manually, you can use the flag " +
 				"-minratio to allow the update to succeed with less servers found")
 		}
-		return fmt.Errorf("getting %s servers: %w", providerName, err)
+		return fmt.Errorf("getting servers: %w", err)
 	}
 
 	for _, server := range servers {

internal/updater/updater.go

@@ -2,11 +2,9 @@ package updater
 
 import (
 	"context"
-	"errors"
 	"net/http"
 	"time"
 
-	"github.com/qdm12/gluetun/internal/provider/common"
 	"github.com/qdm12/gluetun/internal/updater/unzip"
 	"golang.org/x/text/cases"
 	"golang.org/x/text/language"
@@ -50,22 +48,22 @@ func (u *Updater) UpdateServers(ctx context.Context, providers []string,
 		// TODO support servers offering only TCP or only UDP
 		// for NordVPN and PureVPN
 		err := u.updateProvider(ctx, fetcher, minRatio)
-		switch {
+		if err == nil {
-		case err == nil:
 			continue
-		case errors.Is(err, common.ErrCredentialsMissing):
-			u.logger.Warn(err.Error() + " - skipping update for " + providerName)
-			continue
-		case len(providers) == 1:
-			// return the only error for the single provider.
-			return err
-		case ctx.Err() != nil:
-			// stop updating other providers if context is done
-			return ctx.Err()
-		default: // error encountered updating one of multiple providers
-			// Log the error and continue updating the next provider.
-			u.logger.Error(err.Error())
 		}
+
+		// return the only error for the single provider.
+		if len(providers) == 1 {
+			return err
+		}
+
+		// stop updating the next providers if context is canceled.
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			return ctxErr
+		}
+
+		// Log the error and continue updating the next provider.
+		u.logger.Error(err.Error())
 	}
 
 	return nil

internal/vpn/interfaces.go

@@ -81,6 +81,7 @@ type Linker interface {
 	LinkDel(link netlink.Link) (err error)
 	LinkSetUp(link netlink.Link) (linkIndex int, err error)
 	LinkSetDown(link netlink.Link) (err error)
+	LinkSetMTU(link netlink.Link, mtu int) (err error)
 }
 
 type DNSLoop interface {

internal/vpn/run.go

@@ -47,6 +47,7 @@ func (l *Loop) Run(ctx context.Context, done chan<- struct{}) {
 			continue
 		}
 		tunnelUpData := tunnelUpData{
+			vpnType:        settings.Type,
 			serverIP:       connection.IP,
 			serverName:     connection.ServerName,
 			canPortForward: connection.PortForward,

internal/vpn/tunnelup.go

@@ -2,15 +2,24 @@ package vpn
 
 import (
 	"context"
+	"errors"
+	"fmt"
 	"net/netip"
+	"time"
 
+	"github.com/qdm12/dns/v2/pkg/check"
 	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/pmtud"
 	"github.com/qdm12/gluetun/internal/version"
+	"github.com/qdm12/log"
 )
 
 type tunnelUpData struct {
 	// Healthcheck
 	serverIP netip.Addr
+	// vpnType is used for path MTU discovery to find the protocol overhead.
+	// It can be "wireguard" or "openvpn".
+	vpnType string
 	// Port forwarding
 	vpnIntf        string
 	serverName     string // used for PIA
@@ -45,7 +54,21 @@ func (l *Loop) onTunnelUp(ctx, loopCtx context.Context, data tunnelUpData) {
 		return
 	}
 
-	_, _ = l.dnsLooper.ApplyStatus(ctx, constants.Running)
+	mtuLogger := l.logger.New(log.SetComponent("MTU discovery"))
+	err = updateToMaxMTU(ctx, data.vpnIntf, data.vpnType,
+		l.netLinker, l.routing, mtuLogger)
+	if err != nil {
+		mtuLogger.Error(err.Error())
+	}
+
+	if *l.dnsLooper.GetSettings().ServerEnabled {
+		_, _ = l.dnsLooper.ApplyStatus(ctx, constants.Running)
+	} else {
+		err := check.WaitForDNS(ctx, check.Settings{})
+		if err != nil {
+			l.logger.Error("waiting for DNS to be ready: " + err.Error())
+		}
+	}
 
 	err = l.publicip.RunOnce(ctx)
 	if err != nil {
@@ -104,3 +127,65 @@ func (l *Loop) restartVPN(ctx context.Context, healthErr error) {
 	_, _ = l.ApplyStatus(ctx, constants.Stopped)
 	_, _ = l.ApplyStatus(ctx, constants.Running)
 }
+
+var errVPNTypeUnknown = errors.New("unknown VPN type")
+
+func updateToMaxMTU(ctx context.Context, vpnInterface string,
+	vpnType string, netlinker NetLinker, routing Routing, logger *log.Logger,
+) error {
+	logger.Info("finding maximum MTU, this can take up to 4 seconds")
+
+	vpnGatewayIP, err := routing.VPNLocalGatewayIP(vpnInterface)
+	if err != nil {
+		return fmt.Errorf("getting VPN gateway IP address: %w", err)
+	}
+
+	link, err := netlinker.LinkByName(vpnInterface)
+	if err != nil {
+		return fmt.Errorf("getting VPN interface by name: %w", err)
+	}
+
+	originalMTU := link.MTU
+
+	// Note: no point testing for an MTU of 1500, it will never work due to the VPN
+	// protocol overhead, so start lower than 1500 according to the protocol used.
+	const physicalLinkMTU = 1500
+	vpnLinkMTU := physicalLinkMTU
+	switch vpnType {
+	case "wireguard":
+		vpnLinkMTU -= 60 // Wireguard overhead
+	case "openvpn":
+		vpnLinkMTU -= 41 // OpenVPN overhead
+	default:
+		return fmt.Errorf("%w: %q", errVPNTypeUnknown, vpnType)
+	}
+
+	// Setting the VPN link MTU to 1500 might interrupt the connection until
+	// the new MTU is set again, but this is necessary to find the highest valid MTU.
+	logger.Debugf("VPN interface %s MTU temporarily set to %d", vpnInterface, vpnLinkMTU)
+
+	err = netlinker.LinkSetMTU(link, vpnLinkMTU)
+	if err != nil {
+		return fmt.Errorf("setting VPN interface %s MTU to %d: %w", vpnInterface, vpnLinkMTU, err)
+	}
+
+	const pingTimeout = time.Second
+	vpnLinkMTU, err = pmtud.PathMTUDiscover(ctx, vpnGatewayIP, vpnLinkMTU, pingTimeout, logger)
+	switch {
+	case err == nil:
+		logger.Infof("setting VPN interface %s MTU to maximum valid MTU %d", vpnInterface, vpnLinkMTU)
+	case errors.Is(err, pmtud.ErrMTUNotFound) || errors.Is(err, pmtud.ErrICMPNotPermitted):
+		vpnLinkMTU = int(originalMTU)
+		logger.Infof("reverting VPN interface %s MTU to %d (due to: %s)",
+			vpnInterface, originalMTU, err)
+	default:
+		return fmt.Errorf("path MTU discovering: %w", err)
+	}
+
+	err = netlinker.LinkSetMTU(link, vpnLinkMTU)
+	if err != nil {
+		return fmt.Errorf("setting VPN interface %s MTU to %d: %w", vpnInterface, vpnLinkMTU, err)
+	}
+
+	return nil
+}