fix(vpnsecure): allow empty OpenVPN user+password

.devcontainer/Dockerfile

@@ -1,2 +1,2 @@
 FROM qmcgaw/godevcontainer
-RUN apk add wireguard-tools htop openssl
+RUN apk add wireguard-tools htop

.devcontainer/docker-compose.yml

@@ -12,12 +12,14 @@ services:
       # Docker configuration
       - ~/.docker:/root/.docker
       # SSH directory for Linux, OSX and WSL
-      # On Linux and OSX, a symlink /mnt/ssh <-> ~/.ssh is
-      # created in the container. On Windows, files are copied
-      # from /mnt/ssh to ~/.ssh to fix permissions.
-      - ~/.ssh:/mnt/ssh
+      - ~/.ssh:/root/.ssh
+      # For Windows without WSL, a copy will be made
+      # from /tmp/.ssh to ~/.ssh to fix permissions
+      #- ~/.ssh:/tmp/.ssh:ro
       # Shell history persistence
       - ~/.zsh_history:/root/.zsh_history
+      # Git config
+      - ~/.gitconfig:/root/.gitconfig
     environment:
       - TZ=
     cap_add:

.github/ISSUE_TEMPLATE/bug.yml

@@ -40,7 +40,6 @@ body:
     attributes:
       label: VPN service provider
       options:
-        - AirVPN
         - Custom
         - Cyberghost
         - ExpressVPN

.github/labels.yml

@@ -1,13 +1,18 @@
-# Temporary status
-- name: "🗯️ Waiting for feedback"
-  color: "aadefa"
+- name: "Bug :bug:"
+  color: "b60205"
+  description: ""
+- name: "Feature request :bulb:"
+  color: "0e8a16"
+  description: ""
+- name: "Help wanted :pray:"
+  color: "4caf50"
+  description: ""
+- name: "Documentation :memo:"
+  color: "c5def5"
+  description: ""
+- name: "Needs more info :thinking:"
+  color: "795548"
   description: ""
-- name: "🔴 Blocked"
-  color: "ff3f14"
-  description: "Blocked by another issue or pull request"
-- name: "🔒 After next release"
-  color: "e8f274"
-  description: "Will be done after the next release"
 
 # Priority
 - name: "🚨 Urgent"
@@ -17,18 +22,7 @@
   color: "4285f4"
   description: ""
 
-# Complexity
-- name: "☣️ Hard to do"
-  color: "7d0008"
-  description: ""
-- name: "🟩 Easy to do"
-  color: "34cf43"
-  description: ""
-
 # VPN providers
-- name: ":cloud: AirVPN"
-  color: "cfe8d4"
-  description: ""
 - name: ":cloud: Cyberghost"
   color: "cfe8d4"
   description: ""

.github/workflows/ci.yml

@@ -45,8 +45,6 @@ jobs:
         with:
           locale: "US"
           level: error
-          exclude: |
-            ./internal/storage/servers.json
 
       - name: Linting
         run: docker build --target lint .
@@ -93,7 +91,6 @@ jobs:
     permissions:
       actions: read
       contents: read
-      packages: write
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
@@ -107,7 +104,6 @@ jobs:
           flavor: |
             latest=${{ github.ref == format('refs/heads/{0}', github.event.repository.default_branch) }}
           images: |
-            ghcr.io/qdm12/gluetun
             qmcgaw/gluetun
             qmcgaw/private-internet-access
           tags: |
@@ -125,18 +121,12 @@ jobs:
           username: qmcgaw
           password: ${{ secrets.DOCKERHUB_PASSWORD }}
 
-      - uses: docker/login-action@v2
-        with:
-          registry: ghcr.io
-          username: qdm12
-          password: ${{ github.token }}
-
       - name: Short commit
         id: shortcommit
         run: echo "::set-output name=value::$(git rev-parse --short HEAD)"
 
       - name: Build and push final image
-        uses: docker/build-push-action@v4.0.0
+        uses: docker/build-push-action@v3.1.1
         with:
           platforms: linux/amd64,linux/386,linux/arm64,linux/arm/v6,linux/arm/v7,linux/ppc64le
           labels: ${{ steps.meta.outputs.labels }}

.golangci.yml

@@ -29,10 +29,6 @@ issues:
     - text: "returns interface \\(github\\.com\\/vishvananda\\/netlink\\.Link\\)"
       linters:
         - ireturn
-    - path: "internal\\/openvpn\\/pkcs8\\/descbc\\.go"
-      text: "newCipherDESCBCBlock returns interface \\(github\\.com\\/youmark\\/pkcs8\\.Cipher\\)"
-      linters:
-        - ireturn
 
 linters:
   enable:

.vscode/launch.json

@@ -5,11 +5,11 @@
             "name": "Update a VPN provider servers data",
             "type": "go",
             "request": "launch",
-            "cwd": "${workspaceFolder}",
+            "mode": "debug",
             "program": "cmd/gluetun/main.go",
             "args": [
                 "update",
-                "${input:updateMode}",
+                "-enduser",
                 "-providers",
                 "${input:provider}"
             ],
@@ -20,16 +20,6 @@
             "id": "provider",
             "type": "promptString",
             "description": "Please enter a provider (or comma separated list of providers)",
-        },
-        {
-            "id": "updateMode",
-            "type": "pickString",
-            "description": "Update mode to use",
-            "options": [
-                "-maintainer",
-                "-enduser"
-            ],
-            "default": "-maintainer"
-        },
+        }
     ]
 }

Dockerfile

@@ -1,8 +1,8 @@
-ARG ALPINE_VERSION=3.17
-ARG GO_ALPINE_VERSION=3.17
-ARG GO_VERSION=1.20
+ARG ALPINE_VERSION=3.16
+ARG GO_ALPINE_VERSION=3.16
+ARG GO_VERSION=1.17
 ARG XCPUTRANSLATE_VERSION=v0.6.0
-ARG GOLANGCI_LINT_VERSION=v1.52.2
+ARG GOLANGCI_LINT_VERSION=v1.49.0
 ARG MOCKGEN_VERSION=v1.6.0
 ARG BUILDPLATFORM=linux/amd64
 
@@ -91,13 +91,13 @@ ENV VPN_SERVICE_PROVIDER=pia \
     OPENVPN_CIPHERS= \
     OPENVPN_AUTH= \
     OPENVPN_PROCESS_USER= \
+    OPENVPN_IPV6=off \
     OPENVPN_CUSTOM_CONFIG= \
     # Wireguard
     WIREGUARD_PRIVATE_KEY= \
     WIREGUARD_PRESHARED_KEY= \
     WIREGUARD_PUBLIC_KEY= \
     WIREGUARD_ADDRESSES= \
-    WIREGUARD_IMPLEMENTATION=auto \
     # VPN server filtering
     SERVER_REGIONS= \
     SERVER_COUNTRIES= \
@@ -108,8 +108,8 @@ ENV VPN_SERVICE_PROVIDER=pia \
     OWNED_ONLY=no \
     # # Private Internet Access only:
     PRIVATE_INTERNET_ACCESS_OPENVPN_ENCRYPTION_PRESET= \
-    VPN_PORT_FORWARDING=off \
-    VPN_PORT_FORWARDING_STATUS_FILE="/tmp/gluetun/forwarded_port" \
+    PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING=off \
+    PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE="/tmp/gluetun/forwarded_port" \
     # # Cyberghost only:
     OPENVPN_CERT= \
     OPENVPN_KEY= \
@@ -141,7 +141,6 @@ ENV VPN_SERVICE_PROVIDER=pia \
     # Health
     HEALTH_SERVER_ADDRESS=127.0.0.1:9999 \
     HEALTH_TARGET_ADDRESS=cloudflare.com:443 \
-    HEALTH_SUCCESS_WAIT_DURATION=5s \
     HEALTH_VPN_DURATION_INITIAL=6s \
     HEALTH_VPN_DURATION_ADDITION=5s \
     # DNS over TLS
@@ -198,9 +197,8 @@ ENTRYPOINT ["/gluetun-entrypoint"]
 EXPOSE 8000/tcp 8888/tcp 8388/tcp 8388/udp
 HEALTHCHECK --interval=5s --timeout=5s --start-period=10s --retries=1 CMD /gluetun-entrypoint healthcheck
 ARG TARGETPLATFORM
-RUN apk add --no-cache --update -l wget && \
+RUN apk add --no-cache --update -l apk-tools && \
     apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.12/main" openvpn==2.4.12-r0 && \
-    apk add --no-cache --update -X "https://dl-cdn.alpinelinux.org/alpine/v3.16/main" openssl\~1.1 && \
     mv /usr/sbin/openvpn /usr/sbin/openvpn2.4 && \
     apk del openvpn && \
     apk add --no-cache --update openvpn ca-certificates iptables ip6tables unbound tzdata && \

README.md

@@ -1,130 +1,125 @@
-# Gluetun VPN client
-
-Lightweight swiss-knife-like VPN client to multiple VPN service providers
-
-![Title image](https://raw.githubusercontent.com/qdm12/gluetun/master/title.svg)
-
-[![Build status](https://github.com/qdm12/gluetun/actions/workflows/ci.yml/badge.svg)](https://github.com/qdm12/gluetun/actions/workflows/ci.yml)
-
-[![Docker pulls qmcgaw/gluetun](https://img.shields.io/docker/pulls/qmcgaw/gluetun.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
-[![Docker pulls qmcgaw/private-internet-access](https://img.shields.io/docker/pulls/qmcgaw/private-internet-access.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
-
-[![Docker stars qmcgaw/gluetun](https://img.shields.io/docker/stars/qmcgaw/gluetun.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
-[![Docker stars qmcgaw/private-internet-access](https://img.shields.io/docker/stars/qmcgaw/private-internet-access.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
-
-![Last release](https://img.shields.io/github/release/qdm12/gluetun?label=Last%20release)
-![Last Docker tag](https://img.shields.io/docker/v/qmcgaw/gluetun?sort=semver&label=Last%20Docker%20tag)
-[![Last release size](https://img.shields.io/docker/image-size/qmcgaw/gluetun?sort=semver&label=Last%20released%20image)](https://hub.docker.com/r/qmcgaw/gluetun/tags?page=1&ordering=last_updated)
-![GitHub last release date](https://img.shields.io/github/release-date/qdm12/gluetun?label=Last%20release%20date)
-![Commits since release](https://img.shields.io/github/commits-since/qdm12/gluetun/latest?sort=semver)
-
-[![Latest size](https://img.shields.io/docker/image-size/qmcgaw/gluetun/latest?label=Latest%20image)](https://hub.docker.com/r/qmcgaw/gluetun/tags)
-
-[![GitHub last commit](https://img.shields.io/github/last-commit/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/commits/master)
-[![GitHub commit activity](https://img.shields.io/github/commit-activity/y/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/graphs/contributors)
-[![GitHub closed PRs](https://img.shields.io/github/issues-pr-closed/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/pulls?q=is%3Apr+is%3Aclosed)
-[![GitHub issues](https://img.shields.io/github/issues/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues)
-[![GitHub closed issues](https://img.shields.io/github/issues-closed/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues?q=is%3Aissue+is%3Aclosed)
-
-[![Lines of code](https://img.shields.io/tokei/lines/github/qdm12/gluetun)](https://github.com/qdm12/gluetun)
-![Code size](https://img.shields.io/github/languages/code-size/qdm12/gluetun)
-![GitHub repo size](https://img.shields.io/github/repo-size/qdm12/gluetun)
-![Go version](https://img.shields.io/github/go-mod/go-version/qdm12/gluetun)
-
-![Visitors count](https://visitor-badge.laobi.icu/badge?page_id=gluetun.readme)
-
-## Quick links
-
-- [Setup](#Setup)
-- [Features](#Features)
-- Problem?
-  - [Check the Wiki](https://github.com/qdm12/gluetun/wiki)
-  - [Start a discussion](https://github.com/qdm12/gluetun/discussions)
-  - [Fix the Unraid template](https://github.com/qdm12/gluetun/discussions/550)
-- Suggestion?
-  - [Create an issue](https://github.com/qdm12/gluetun/issues)
-  - [Join the Slack channel](https://join.slack.com/t/qdm12/shared_invite/enQtOTE0NjcxNTM1ODc5LTYyZmVlOTM3MGI4ZWU0YmJkMjUxNmQ4ODQ2OTAwYzMxMTlhY2Q1MWQyOWUyNjc2ODliNjFjMDUxNWNmNzk5MDk)
-- Happy?
-  - Sponsor me on [github.com/sponsors/qdm12](https://github.com/sponsors/qdm12)
-  - Donate to [paypal.me/qmcgaw](https://www.paypal.me/qmcgaw)
-  - Drop me [an email](mailto:quentin.mcgaw@gmail.com)
-- **Want to add a VPN provider?** check [Development](https://github.com/qdm12/gluetun/wiki/Development) and [Add a provider](https://github.com/qdm12/gluetun/wiki/Add-a-provider)
-- Video:
-
-  [![Video Gif](https://i.imgur.com/CetWunc.gif)](https://youtu.be/0F6I03LQcI4)
-
-- [Substack Console interview](https://console.substack.com/p/console-72)
-
-## Features
-
-- Based on Alpine 3.17 for a small Docker image of 42MB
-- Supports: **AirVPN**, **Cyberghost**, **ExpressVPN**, **FastestVPN**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad**, **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **WeVPN**, **Windscribe** servers
-- Supports OpenVPN for all providers listed
-- Supports Wireguard both kernelspace and userspace
-  - For **Mullvad**, **Ivpn**, **Surfshark** and **Windscribe**
-  - For **ProtonVPN**, **PureVPN**, **Torguard**, **VPN Unlimited** and **WeVPN** using [the custom provider](https://github.com/qdm12/gluetun/wiki/Custom-provider)
-  - For custom Wireguard configurations using [the custom provider](https://github.com/qdm12/gluetun/wiki/Custom-provider)
-  - More in progress, see [#134](https://github.com/qdm12/gluetun/issues/134)
-- DNS over TLS baked in with service provider(s) of your choice
-- DNS fine blocking of malicious/ads/surveillance hostnames and IP addresses, with live update every 24 hours
-- Choose the vpn network protocol, `udp` or `tcp`
-- Built in firewall kill switch to allow traffic only with needed the VPN servers and LAN devices
-- Built in Shadowsocks proxy (protocol based on SOCKS5 with an encryption layer, tunnels TCP+UDP)
-- Built in HTTP proxy (tunnels HTTP and HTTPS through TCP)
-- [Connect other containers to it](https://github.com/qdm12/gluetun/wiki/Connect-a-container-to-gluetun)
-- [Connect LAN devices to it](https://github.com/qdm12/gluetun/wiki/Connect-a-LAN-device-to-gluetun)
-- Compatible with amd64, i686 (32 bit), **ARM** 64 bit, ARM 32 bit v6 and v7, and even ppc64le 🎆
-- [Custom VPN server side port forwarding for Private Internet Access](https://github.com/qdm12/gluetun/wiki/Private-internet-access#vpn-server-port-forwarding)
-- Possibility of split horizon DNS by selecting multiple DNS over TLS providers
-- Unbound subprogram drops root privileges once launched
-- Can work as a Kubernetes sidecar container, thanks @rorph
-
-## Setup
-
-🎉 There are now instructions specific to each VPN provider with examples to help you get started as quickly as possible!
-
-Go to the [Wiki](https://github.com/qdm12/gluetun/wiki)!
-
-[🐛 Found a bug in the Wiki?!](https://github.com/qdm12/gluetun/issues/new?assignees=&labels=%F0%9F%93%84+Wiki+issue&template=wiki+issue.yml&title=Wiki+issue%3A+)
-
-Here's a docker-compose.yml for the laziest:
-
-```yml
-version: "3"
-services:
-  gluetun:
-    image: qmcgaw/gluetun
-    # container_name: gluetun
-    # line above must be uncommented to allow external containers to connect. See https://github.com/qdm12/gluetun/wiki/Connect-a-container-to-gluetun#external-container-to-gluetun
-    cap_add:
-      - NET_ADMIN
-    devices:
-      - /dev/net/tun:/dev/net/tun
-    ports:
-      - 8888:8888/tcp # HTTP proxy
-      - 8388:8388/tcp # Shadowsocks
-      - 8388:8388/udp # Shadowsocks
-    volumes:
-      - /yourpath:/gluetun
-    environment:
-      # See https://github.com/qdm12/gluetun/wiki
-      - VPN_SERVICE_PROVIDER=ivpn
-      - VPN_TYPE=openvpn
-      # OpenVPN:
-      - OPENVPN_USER=
-      - OPENVPN_PASSWORD=
-      # Wireguard:
-      # - WIREGUARD_PRIVATE_KEY=wOEI9rqqbDwnN8/Bpp22sVz48T71vJ4fYmFWujulwUU=
-      # - WIREGUARD_ADDRESSES=10.64.222.21/32
-      # Timezone for accurate log times
-      - TZ=
-      # Server list updater. See https://github.com/qdm12/gluetun/wiki/Updating-Servers#periodic-update
-      - UPDATER_PERIOD=
-      - UPDATER_VPN_SERVICE_PROVIDERS=
-```
-
-🆕 Image also available as `ghcr.io/qdm12/gluetun`
-
-## License
-
-[![MIT](https://img.shields.io/github/license/qdm12/gluetun)](https://github.com/qdm12/gluetun/master/LICENSE)
+# Gluetun VPN client
+
+Lightweight swiss-knife-like VPN client to multiple VPN service providers
+
+![Title image](https://raw.githubusercontent.com/qdm12/gluetun/master/title.svg)
+
+[![Build status](https://github.com/qdm12/gluetun/actions/workflows/ci.yml/badge.svg)](https://github.com/qdm12/gluetun/actions/workflows/ci.yml)
+
+[![Docker pulls qmcgaw/gluetun](https://img.shields.io/docker/pulls/qmcgaw/gluetun.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
+[![Docker pulls qmcgaw/private-internet-access](https://img.shields.io/docker/pulls/qmcgaw/private-internet-access.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
+
+[![Docker stars qmcgaw/gluetun](https://img.shields.io/docker/stars/qmcgaw/gluetun.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
+[![Docker stars qmcgaw/private-internet-access](https://img.shields.io/docker/stars/qmcgaw/private-internet-access.svg)](https://hub.docker.com/r/qmcgaw/gluetun)
+
+![Last release](https://img.shields.io/github/release/qdm12/gluetun?label=Last%20release)
+![Last Docker tag](https://img.shields.io/docker/v/qmcgaw/gluetun?sort=semver&label=Last%20Docker%20tag)
+[![Last release size](https://img.shields.io/docker/image-size/qmcgaw/gluetun?sort=semver&label=Last%20released%20image)](https://hub.docker.com/r/qmcgaw/gluetun/tags?page=1&ordering=last_updated)
+![GitHub last release date](https://img.shields.io/github/release-date/qdm12/gluetun?label=Last%20release%20date)
+![Commits since release](https://img.shields.io/github/commits-since/qdm12/gluetun/latest?sort=semver)
+
+[![Latest size](https://img.shields.io/docker/image-size/qmcgaw/gluetun/latest?label=Latest%20image)](https://hub.docker.com/r/qmcgaw/gluetun/tags)
+
+[![GitHub last commit](https://img.shields.io/github/last-commit/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/commits/master)
+[![GitHub commit activity](https://img.shields.io/github/commit-activity/y/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/graphs/contributors)
+[![GitHub closed PRs](https://img.shields.io/github/issues-pr-closed/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/pulls?q=is%3Apr+is%3Aclosed)
+[![GitHub issues](https://img.shields.io/github/issues/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues)
+[![GitHub closed issues](https://img.shields.io/github/issues-closed/qdm12/gluetun.svg)](https://github.com/qdm12/gluetun/issues?q=is%3Aissue+is%3Aclosed)
+
+[![Lines of code](https://img.shields.io/tokei/lines/github/qdm12/gluetun)](https://github.com/qdm12/gluetun)
+![Code size](https://img.shields.io/github/languages/code-size/qdm12/gluetun)
+![GitHub repo size](https://img.shields.io/github/repo-size/qdm12/gluetun)
+![Go version](https://img.shields.io/github/go-mod/go-version/qdm12/gluetun)
+
+![Visitors count](https://visitor-badge.laobi.icu/badge?page_id=gluetun.readme)
+
+## Quick links
+
+- [Setup](#Setup)
+- [Features](#Features)
+- Problem?
+  - [Check the Wiki](https://github.com/qdm12/gluetun/wiki)
+  - [Start a discussion](https://github.com/qdm12/gluetun/discussions)
+  - [Fix the Unraid template](https://github.com/qdm12/gluetun/discussions/550)
+- Suggestion?
+  - [Create an issue](https://github.com/qdm12/gluetun/issues)
+  - [Join the Slack channel](https://join.slack.com/t/qdm12/shared_invite/enQtOTE0NjcxNTM1ODc5LTYyZmVlOTM3MGI4ZWU0YmJkMjUxNmQ4ODQ2OTAwYzMxMTlhY2Q1MWQyOWUyNjc2ODliNjFjMDUxNWNmNzk5MDk)
+- Happy?
+  - Sponsor me on [github.com/sponsors/qdm12](https://github.com/sponsors/qdm12)
+  - Donate to [paypal.me/qmcgaw](https://www.paypal.me/qmcgaw)
+  - Drop me [an email](mailto:quentin.mcgaw@gmail.com)
+- **Want to add a VPN provider?** check [Development](https://github.com/qdm12/gluetun/wiki/Development) and [Add a provider](https://github.com/qdm12/gluetun/wiki/Add-a-provider)
+- Video:
+
+  [![Video Gif](https://i.imgur.com/CetWunc.gif)](https://youtu.be/0F6I03LQcI4)
+
+- [Substack Console interview](https://console.substack.com/p/console-72)
+
+## Features
+
+- Based on Alpine 3.16 for a small Docker image of 29MB
+- Supports: **Cyberghost**, **ExpressVPN**, **FastestVPN**, **HideMyAss**, **IPVanish**, **IVPN**, **Mullvad**, **NordVPN**, **Perfect Privacy**, **Privado**, **Private Internet Access**, **PrivateVPN**, **ProtonVPN**, **PureVPN**,  **SlickVPN**, **Surfshark**, **TorGuard**, **VPNSecure.me**, **VPNUnlimited**, **Vyprvpn**, **WeVPN**, **Windscribe** servers
+- Supports OpenVPN for all providers listed
+- Supports Wireguard both kernelspace and userspace
+  - For **Mullvad**, **Ivpn** and **Windscribe**
+  - For **Torguard**, **VPN Unlimited** and **WeVPN** using [the custom provider](https://github.com/qdm12/gluetun/wiki/Custom-provider)
+  - For custom Wireguard configurations using [the custom provider](https://github.com/qdm12/gluetun/wiki/Custom-provider)
+  - More in progress, see [#134](https://github.com/qdm12/gluetun/issues/134)
+- DNS over TLS baked in with service provider(s) of your choice
+- DNS fine blocking of malicious/ads/surveillance hostnames and IP addresses, with live update every 24 hours
+- Choose the vpn network protocol, `udp` or `tcp`
+- Built in firewall kill switch to allow traffic only with needed the VPN servers and LAN devices
+- Built in Shadowsocks proxy (protocol based on SOCKS5 with an encryption layer, tunnels TCP+UDP)
+- Built in HTTP proxy (tunnels HTTP and HTTPS through TCP)
+- [Connect other containers to it](https://github.com/qdm12/gluetun/wiki/Connect-a-container-to-gluetun)
+- [Connect LAN devices to it](https://github.com/qdm12/gluetun/wiki/Connect-a-LAN-device-to-gluetun)
+- Compatible with amd64, i686 (32 bit), **ARM** 64 bit, ARM 32 bit v6 and v7, and even ppc64le 🎆
+- [Custom VPN server side port forwarding for Private Internet Access](https://github.com/qdm12/gluetun/wiki/Private-internet-access#vpn-server-port-forwarding)
+- Possibility of split horizon DNS by selecting multiple DNS over TLS providers
+- Unbound subprogram drops root privileges once launched
+- Can work as a Kubernetes sidecar container, thanks @rorph
+
+## Setup
+
+🎉 There are now instructions specific to each VPN provider with examples to help you get started as quickly as possible!
+
+Go to the [Wiki](https://github.com/qdm12/gluetun/wiki)!
+
+[🐛 Found a bug in the Wiki?!](https://github.com/qdm12/gluetun/issues/new?assignees=&labels=%F0%9F%93%84+Wiki+issue&template=wiki+issue.yml&title=Wiki+issue%3A+)
+
+Here's a docker-compose.yml for the laziest:
+
+```yml
+version: "3"
+services:
+  gluetun:
+    image: qmcgaw/gluetun
+    # container_name: gluetun
+    # line above must be uncommented to allow external containers to connect. See https://github.com/qdm12/gluetun/wiki/Connect-a-container-to-gluetun#external-container-to-gluetun
+    cap_add:
+      - NET_ADMIN
+    devices:
+      - /dev/net/tun:/dev/net/tun
+    ports:
+      - 8888:8888/tcp # HTTP proxy
+      - 8388:8388/tcp # Shadowsocks
+      - 8388:8388/udp # Shadowsocks
+    volumes:
+      - /yourpath:/gluetun
+    environment:
+      # See https://github.com/qdm12/gluetun/wiki
+      - VPN_SERVICE_PROVIDER=ivpn
+      - VPN_TYPE=openvpn
+      # OpenVPN:
+      - OPENVPN_USER=
+      - OPENVPN_PASSWORD=
+      # Wireguard:
+      # - WIREGUARD_PRIVATE_KEY=wOEI9rqqbDwnN8/Bpp22sVz48T71vJ4fYmFWujulwUU=
+      # - WIREGUARD_ADDRESSES=10.64.222.21/32
+      # Timezone for accurate log times
+      - TZ=
+```
+
+## License
+
+[![MIT](https://img.shields.io/github/license/qdm12/gluetun)](https://github.com/qdm12/gluetun/master/LICENSE)

cmd/gluetun/main.go

@@ -16,10 +16,10 @@ import (
 	"github.com/qdm12/dns/pkg/unbound"
 	"github.com/qdm12/gluetun/internal/alpine"
 	"github.com/qdm12/gluetun/internal/cli"
-	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 	"github.com/qdm12/gluetun/internal/configuration/sources/env"
 	"github.com/qdm12/gluetun/internal/configuration/sources/files"
-	mux "github.com/qdm12/gluetun/internal/configuration/sources/merge"
+	"github.com/qdm12/gluetun/internal/configuration/sources/mux"
 	"github.com/qdm12/gluetun/internal/configuration/sources/secrets"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/dns"
@@ -77,8 +77,7 @@ func main() {
 
 	args := os.Args
 	tun := tun.New()
-	netLinkDebugLogger := logger.New(log.SetComponent("netlink"))
-	netLinker := netlink.New(netLinkDebugLogger)
+	netLinker := netlink.New()
 	cli := cli.New()
 	cmder := command.NewCmder()
 
@@ -92,13 +91,12 @@ func main() {
 		errorCh <- _main(ctx, buildInfo, args, logger, muxReader, tun, netLinker, cmder, cli)
 	}()
 
-	var err error
 	select {
 	case signal := <-signalCh:
 		fmt.Println("")
 		logger.Warn("Caught OS signal " + signal.String() + ", shutting down")
 		cancel()
-	case err = <-errorCh:
+	case err := <-errorCh:
 		close(errorCh)
 		if err == nil { // expected exit such as healthcheck
 			os.Exit(0)
@@ -110,27 +108,18 @@ func main() {
 	const shutdownGracePeriod = 5 * time.Second
 	timer := time.NewTimer(shutdownGracePeriod)
 	select {
-	case shutdownErr := <-errorCh:
+	case <-errorCh:
 		if !timer.Stop() {
 			<-timer.C
 		}
-		if shutdownErr != nil {
-			logger.Warnf("Shutdown not completed gracefully: %s", shutdownErr)
-			os.Exit(1)
-		}
-
 		logger.Info("Shutdown successful")
-		if err != nil {
-			os.Exit(1)
-		}
-		os.Exit(0)
 	case <-timer.C:
 		logger.Warn("Shutdown timed out")
-		os.Exit(1)
 	case signal := <-signalCh:
 		logger.Warn("Caught OS signal " + signal.String() + ", forcing shut down")
-		os.Exit(1)
 	}
+
+	os.Exit(1)
 }
 
 var (
@@ -139,7 +128,7 @@ var (
 
 //nolint:gocognit,gocyclo,maintidx
 func _main(ctx context.Context, buildInfo models.BuildInformation,
-	args []string, logger log.LoggerInterface, source Source,
+	args []string, logger log.LoggerInterface, source sources.Source,
 	tun Tun, netLinker netLinker, cmder command.RunStarter,
 	cli clier) error {
 	if len(args) > 1 { // cli operation
@@ -149,7 +138,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		case "clientkey":
 			return cli.ClientKey(args[2:])
 		case "openvpnconfig":
-			return cli.OpenvpnConfig(logger, source, netLinker)
+			return cli.OpenvpnConfig(logger, source)
 		case "update":
 			return cli.Update(ctx, args[2:], logger)
 		case "format-servers":
@@ -190,7 +179,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	// - firewall Debug and Enabled are booleans parsed from source
 
 	logger.Patch(log.SetLevel(*allSettings.Log.Level))
-	netLinker.PatchLoggerLevel(*allSettings.Log.Level)
 
 	routingLogger := logger.New(log.SetComponent("routing"))
 	if *allSettings.Firewall.Debug { // To remove in v4
@@ -232,12 +220,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		return err
 	}
 
-	ipv6Supported, err := netLinker.IsIPv6Supported()
-	if err != nil {
-		return fmt.Errorf("checking for IPv6 support: %w", err)
-	}
-
-	err = allSettings.Validate(storage, ipv6Supported)
+	err = allSettings.Validate(storage)
 	if err != nil {
 		return err
 	}
@@ -245,7 +228,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	allSettings.Pprof.HTTPServer.Logger = logger.New(log.SetComponent("pprof"))
 	pprofServer, err := pprof.New(allSettings.Pprof)
 	if err != nil {
-		return fmt.Errorf("creating Pprof server: %w", err)
+		return fmt.Errorf("cannot create Pprof server: %w", err)
 	}
 
 	puid, pgid := int(*allSettings.System.PUID), int(*allSettings.System.PGID)
@@ -277,10 +260,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 
 	logger.Info(allSettings.String())
 
-	for _, warning := range allSettings.Warnings() {
-		logger.Warn(warning)
-	}
-
 	if err := os.MkdirAll("/tmp/gluetun", 0644); err != nil {
 		return err
 	}
@@ -291,7 +270,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	const defaultUsername = "nonrootuser"
 	nonRootUsername, err := alpineConf.CreateUser(defaultUsername, puid)
 	if err != nil {
-		return fmt.Errorf("creating user: %w", err)
+		return fmt.Errorf("cannot create user: %w", err)
 	}
 	if nonRootUsername != defaultUsername {
 		logger.Info("using existing username " + nonRootUsername + " corresponding to user id " + fmt.Sprint(puid))
@@ -309,7 +288,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		if strings.Contains(err.Error(), "operation not permitted") {
 			logger.Warn("💡 Tip: Are you passing NET_ADMIN capability to gluetun?")
 		}
-		return fmt.Errorf("setting up routing: %w", err)
+		return fmt.Errorf("cannot setup routing: %w", err)
 	}
 	defer func() {
 		routingLogger.Info("routing cleanup...")
@@ -325,11 +304,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		return err
 	}
 
-	err = routingConf.AddLocalRules(localNetworks)
-	if err != nil {
-		return fmt.Errorf("adding local rules: %w", err)
-	}
-
 	const tunDevice = "/dev/net/tun"
 	if err := tun.Check(tunDevice); err != nil {
 		logger.Info(err.Error() + "; creating it...")
@@ -365,14 +339,11 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 	tickersGroupHandler := goshutdown.NewGroupHandler("tickers", defaultGroupOptions...)
 	otherGroupHandler := goshutdown.NewGroupHandler("other", defaultGroupOptions...)
 
-	if *allSettings.Pprof.Enabled {
-		// TODO run in run loop so this can be patched at runtime
-		pprofReady := make(chan struct{})
-		pprofHandler, pprofCtx, pprofDone := goshutdown.NewGoRoutineHandler("pprof server")
-		go pprofServer.Run(pprofCtx, pprofReady, pprofDone)
-		otherGroupHandler.Add(pprofHandler)
-		<-pprofReady
-	}
+	pprofReady := make(chan struct{})
+	pprofHandler, pprofCtx, pprofDone := goshutdown.NewGoRoutineHandler("pprof server")
+	go pprofServer.Run(pprofCtx, pprofReady, pprofDone)
+	otherGroupHandler.Add(pprofHandler)
+	<-pprofReady
 
 	portForwardLogger := logger.New(log.SetComponent("port forwarding"))
 	portForwardLooper := portforward.NewLoop(allSettings.VPN.Provider.PortForwarding,
@@ -418,7 +389,7 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		httpClient, unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
 
 	vpnLogger := logger.New(log.SetComponent("vpn"))
-	vpnLooper := vpn.NewLoop(allSettings.VPN, ipv6Supported, allSettings.Firewall.VPNInputPorts,
+	vpnLooper := vpn.NewLoop(allSettings.VPN, allSettings.Firewall.VPNInputPorts,
 		providers, storage, ovpnConf, netLinker, firewallConf, routingConf, portForwardLooper,
 		cmder, publicIPLooper, unboundLooper, vpnLogger, httpClient,
 		buildInfo, *allSettings.Version.Enabled)
@@ -460,10 +431,9 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		"http server", goroutine.OptionTimeout(defaultShutdownTimeout))
 	httpServer, err := server.New(httpServerCtx, controlServerAddress, controlServerLogging,
 		logger.New(log.SetComponent("http server")),
-		buildInfo, vpnLooper, portForwardLooper, unboundLooper, updaterLooper, publicIPLooper,
-		storage, ipv6Supported)
+		buildInfo, vpnLooper, portForwardLooper, unboundLooper, updaterLooper, publicIPLooper, storage)
 	if err != nil {
-		return fmt.Errorf("setting up control server: %w", err)
+		return fmt.Errorf("cannot setup control server: %w", err)
 	}
 	httpServerReady := make(chan struct{})
 	go httpServer.Run(httpServerCtx, httpServerReady, httpServerDone)
@@ -510,7 +480,7 @@ func printVersions(ctx context.Context, logger infoer,
 	for _, element := range elements {
 		version, err := element.getVersion(ctx)
 		if err != nil {
-			return fmt.Errorf("getting %s version: %w", element.name, err)
+			return err
 		}
 		logger.Info(element.name + " version: " + version)
 	}
@@ -524,8 +494,6 @@ type netLinker interface {
 	Ruler
 	Linker
 	IsWireguardSupported() (ok bool, err error)
-	IsIPv6Supported() (ok bool, err error)
-	PatchLoggerLevel(level log.Level)
 }
 
 type Addresser interface {
@@ -561,8 +529,8 @@ type Linker interface {
 type clier interface {
 	ClientKey(args []string) error
 	FormatServers(args []string) error
-	OpenvpnConfig(logger cli.OpenvpnConfigLogger, source cli.Source, ipv6Checker cli.IPv6Checker) error
-	HealthCheck(ctx context.Context, source cli.Source, warner cli.Warner) error
+	OpenvpnConfig(logger cli.OpenvpnConfigLogger, source sources.Source) error
+	HealthCheck(ctx context.Context, source sources.Source, warner cli.Warner) error
 	Update(ctx context.Context, args []string, logger cli.UpdaterLogger) error
 }
 
@@ -570,9 +538,3 @@ type Tun interface {
 	Check(tunDevice string) error
 	Create(tunDevice string) error
 }
-
-type Source interface {
-	Read() (settings settings.Settings, err error)
-	ReadHealth() (health settings.Health, err error)
-	String() string
-}

go.mod

@@ -1,10 +1,10 @@
 module github.com/qdm12/gluetun
 
-go 1.20
+go 1.17
 
 require (
-	github.com/breml/rootcerts v0.2.10
-	github.com/fatih/color v1.15.0
+	github.com/breml/rootcerts v0.2.6
+	github.com/fatih/color v1.13.0
 	github.com/golang/mock v1.6.0
 	github.com/qdm12/dns v1.11.0
 	github.com/qdm12/golibs v0.0.0-20210822203818-5c568b0777b6
@@ -15,36 +15,31 @@ require (
 	github.com/qdm12/log v0.1.0
 	github.com/qdm12/ss-server v0.4.0
 	github.com/qdm12/updated v0.0.0-20210603204757-205acfe6937e
-	github.com/stretchr/testify v1.8.2
-	github.com/vishvananda/netlink v1.2.1-beta.2
-	github.com/youmark/pkcs8 v0.0.0-20201027041543-1326539a0a0a
-	golang.org/x/exp v0.0.0-20230519143937-03e91628a987
-	golang.org/x/net v0.10.0
-	golang.org/x/sys v0.8.0
-	golang.org/x/text v0.9.0
-	golang.zx2c4.com/wireguard v0.0.0-20230325221338-052af4a8072b
-	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230215201556-9c5414ab4bde
-	inet.af/netaddr v0.0.0-20220811202034-502d2d690317
+	github.com/stretchr/testify v1.8.0
+	github.com/vishvananda/netlink v1.1.1-0.20211129163951-9ada19101fc5
+	golang.org/x/net v0.0.0-20210916014120-12bc252f5db8
+	golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c
+	golang.org/x/text v0.3.7
+	golang.zx2c4.com/wireguard v0.0.0-20210805125648-3957e9b9dd19
+	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20210803171230-4253848d036c
+	inet.af/netaddr v0.0.0-20210718074554-06ca8145d722
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/google/go-cmp v0.5.9 // indirect
-	github.com/josharian/native v1.0.0 // indirect
-	github.com/mattn/go-colorable v0.1.13 // indirect
-	github.com/mattn/go-isatty v0.0.17 // indirect
-	github.com/mdlayher/genetlink v1.2.0 // indirect
-	github.com/mdlayher/netlink v1.6.2 // indirect
-	github.com/mdlayher/socket v0.2.3 // indirect
+	github.com/google/go-cmp v0.5.5 // indirect
+	github.com/josharian/native v0.0.0-20200817173448-b6b71def0850 // indirect
+	github.com/mattn/go-colorable v0.1.9 // indirect
+	github.com/mattn/go-isatty v0.0.14 // indirect
+	github.com/mdlayher/genetlink v1.0.0 // indirect
+	github.com/mdlayher/netlink v1.4.0 // indirect
 	github.com/miekg/dns v1.1.40 // indirect
 	github.com/mr-tron/base58 v1.2.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/riobard/go-bloom v0.0.0-20200614022211-cdc8013cb5b3 // indirect
 	github.com/vishvananda/netns v0.0.0-20200728191858-db3c7e526aae // indirect
-	go4.org/intern v0.0.0-20211027215823-ae77deb06f29 // indirect
-	go4.org/unsafe/assume-no-moving-gc v0.0.0-20230221090011-e4bae7ad2296 // indirect
-	golang.org/x/crypto v0.6.0 // indirect
-	golang.org/x/sync v0.1.0 // indirect
-	golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 // indirect
+	go4.org/intern v0.0.0-20210108033219-3eb7198706b2 // indirect
+	go4.org/unsafe/assume-no-moving-gc v0.0.0-20220617031537-928513b29760 // indirect
+	golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -4,8 +4,8 @@ github.com/alcortesm/tgz v0.0.0-20161220082320-9c5fe88206d7/go.mod h1:6zEj6s6u/g
 github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239/go.mod h1:2FmKhYUyUczH0OGQWaF5ceTx0UBShxjsH6f8oGKYe2c=
 github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/asaskevich/govalidator v0.0.0-20180720115003-f9ffefc3facf/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=
-github.com/breml/rootcerts v0.2.10 h1:UGVZ193UTSUASpGtg6pbDwzOd7XQP+at0Ssg1/2E4h8=
-github.com/breml/rootcerts v0.2.10/go.mod h1:24FDtzYMpqIeYC7QzaE8VPRQaFZU5TIUDlyk8qwjD88=
+github.com/breml/rootcerts v0.2.6 h1:CdPczjzItec+wopLoDsBAFcLEai2q7Yayfg/94/q/2E=
+github.com/breml/rootcerts v0.2.6/go.mod h1:24FDtzYMpqIeYC7QzaE8VPRQaFZU5TIUDlyk8qwjD88=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -14,8 +14,8 @@ github.com/docker/go-units v0.3.3/go.mod h1:fgPhTUdO+D/Jk86RDLlptpiXQzgHJF7gydDD
 github.com/dvyukov/go-fuzz v0.0.0-20210103155950-6a8e9d1f2415/go.mod h1:11Gm+ccJnvAhCNLlf5+cS9KjtbaD5I5zaZpFMsTHWTw=
 github.com/emirpasic/gods v1.12.0/go.mod h1:YfzfFFoVP/catgzJb4IKIqXjX78Ha8FMSDh3ymbK86o=
 github.com/fatih/color v1.12.0/go.mod h1:ELkj/draVOlAH/xkhN6mQ50Qd0MPOk5AAr3maGEBuJM=
-github.com/fatih/color v1.15.0 h1:kOqh6YHBtK8aywxGerMG2Eq3H6Qgoqeo13Bk2Mv/nBs=
-github.com/fatih/color v1.15.0/go.mod h1:0h5ZqXfHYED7Bhv2ZJamyIOUej9KtShiJESRwBDUSsw=
+github.com/fatih/color v1.13.0 h1:8LOYc1KYPPmyKMuN8QV2DNRWNbLo6LZ0iLs8+mlH53w=
+github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=
 github.com/flynn/go-shlex v0.0.0-20150515145356-3f9db97f8568/go.mod h1:xEzjJPgXI435gkrCt3MPfRiAkVrwSbHsst4LCFVfpJc=
 github.com/gliderlabs/ssh v0.2.2/go.mod h1:U7qILu1NlMHj9FlMhZLlkCdDnU1DBEAqr0aevW3Awn0=
 github.com/globalsign/mgo v0.0.0-20180905125535-1ca0a4f7cbcb/go.mod h1:xkRDCp4j0OGD1HRkm4kmhM+pmpv3AKq5SU7GMg4oO/Q=
@@ -36,18 +36,28 @@ github.com/golang/mock v1.5.0/go.mod h1:CWnOUgYIOo4TcNZ0wHX3YZCqsaM1I1Jvs6v3mP3K
 github.com/golang/mock v1.6.0 h1:ErTB+efbowRARo13NNdxyJji2egdxLGQhRaY+DUumQc=
 github.com/golang/mock v1.6.0/go.mod h1:p6yTPP+5HYm5mzsMV8JkE6ZKdX+/wYM6Hr+LicevLPs=
 github.com/gomodule/redigo v2.0.0+incompatible/go.mod h1:B4C85qUVwatsJoIUNIfCRsp7qO0iAmpGFZ4EELWSbC4=
-github.com/google/btree v1.0.1 h1:gK4Kx5IaGY9CD5sPJ36FHiBJ6ZXl0kilRiiCj+jdYp4=
+github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
 github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
-github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.3.1/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
+github.com/google/go-cmp v0.4.0/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
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-golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=
-golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
-golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
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@@ -218,13 +237,13 @@ golang.org/x/tools v0.1.1/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
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 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.zx2c4.com/wintun v0.0.0-20230126152724-0fa3db229ce2 h1:B82qJJgjvYKsXS9jeunTOisW56dUokqW/FOteYJJ/yg=
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-golang.zx2c4.com/wireguard v0.0.0-20230325221338-052af4a8072b/go.mod h1:tqur9LnfstdR9ep2LaJT4lFUl0EjlHtge+gAjmsHUG4=
-golang.zx2c4.com/wireguard/wgctrl v0.0.0-20230215201556-9c5414ab4bde h1:ybF7AMzIUikL9x4LgwEmzhXtzRpKNqngme1VGDWz+Nk=
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+golang.zx2c4.com/wireguard/wgctrl v0.0.0-20210803171230-4253848d036c h1:ADNrRDI5NR23/TUCnEmlLZLt4u9DnZ2nwRkPrAcFvto=
+golang.zx2c4.com/wireguard/wgctrl v0.0.0-20210803171230-4253848d036c/go.mod h1:+1XihzyZUBJcSc5WO9SwNA7v26puQwOEDwanaxfNXPQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 h1:qIbj1fsPNlZgppZ+VLlY7N33q108Sa+fhmuc+sWQYwY=
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@@ -237,7 +256,6 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-gvisor.dev/gvisor v0.0.0-20221203005347-703fd9b7fbc0 h1:Wobr37noukisGxpKo5jAsLREcpj61RxrWYzD8uwveOY=
 inet.af/netaddr v0.0.0-20210511181906-37180328850c/go.mod h1:z0nx+Dh+7N7CC8V5ayHtHGpZpxLQZZxkIaaz6HN65Ls=
-inet.af/netaddr v0.0.0-20220811202034-502d2d690317 h1:U2fwK6P2EqmopP/hFLTOAjWTki0qgd4GMJn5X8wOleU=
-inet.af/netaddr v0.0.0-20220811202034-502d2d690317/go.mod h1:OIezDfdzOgFhuw4HuWapWq2e9l0H9tK4F1j+ETRtF3k=
+inet.af/netaddr v0.0.0-20210718074554-06ca8145d722 h1:Qws2rZnQudC58cIagVucPQDLmMi3kAXgxscsgD0v6DU=
+inet.af/netaddr v0.0.0-20210718074554-06ca8145d722/go.mod h1:z0nx+Dh+7N7CC8V5ayHtHGpZpxLQZZxkIaaz6HN65Ls=

internal/alpine/version.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 )
 
-func (a *Alpine) Version(context.Context) (version string, err error) {
+func (a *Alpine) Version(ctx context.Context) (version string, err error) {
 	file, err := os.OpenFile(a.alpineReleasePath, os.O_RDONLY, 0)
 	if err != nil {
 		return "", err

internal/cli/ci.go

@@ -2,6 +2,6 @@ package cli
 
 import "context"
 
-func (c *CLI) CI(context.Context) error {
+func (c *CLI) CI(context context.Context) error {
 	return nil
 }

internal/cli/formatservers.go

@@ -61,7 +61,7 @@ func (c *CLI) FormatServers(args []string) error {
 	}
 	switch len(providers) {
 	case 0:
-		return fmt.Errorf("%w", ErrProviderUnspecified)
+		return ErrProviderUnspecified
 	case 1:
 	default:
 		return fmt.Errorf("%w: %d specified: %s",
@@ -73,7 +73,7 @@ func (c *CLI) FormatServers(args []string) error {
 	logger := newNoopLogger()
 	storage, err := storage.New(logger, constants.ServersData)
 	if err != nil {
-		return fmt.Errorf("creating servers storage: %w", err)
+		return fmt.Errorf("cannot create servers storage: %w", err)
 	}
 
 	formatted := storage.FormatToMarkdown(providerToFormat)
@@ -81,18 +81,18 @@ func (c *CLI) FormatServers(args []string) error {
 	output = filepath.Clean(output)
 	file, err := os.OpenFile(output, os.O_TRUNC|os.O_WRONLY|os.O_CREATE, 0644)
 	if err != nil {
-		return fmt.Errorf("opening output file: %w", err)
+		return fmt.Errorf("cannot open output file: %w", err)
 	}
 
 	_, err = fmt.Fprint(file, formatted)
 	if err != nil {
 		_ = file.Close()
-		return fmt.Errorf("writing to output file: %w", err)
+		return fmt.Errorf("cannot write to output file: %w", err)
 	}
 
 	err = file.Close()
 	if err != nil {
-		return fmt.Errorf("closing output file: %w", err)
+		return fmt.Errorf("cannot close output file: %w", err)
 	}
 
 	return nil

internal/cli/healthcheck.go

@@ -6,18 +6,17 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 	"github.com/qdm12/gluetun/internal/healthcheck"
 )
 
-func (c *CLI) HealthCheck(ctx context.Context, source Source, _ Warner) error {
+func (c *CLI) HealthCheck(ctx context.Context, source sources.Source, warner Warner) error {
 	// Extract the health server port from the configuration.
 	config, err := source.ReadHealth()
 	if err != nil {
 		return err
 	}
 
-	config.SetDefaults()
-
 	err = config.Validate()
 	if err != nil {
 		return err

internal/cli/nooplogger.go

@@ -8,9 +8,9 @@ func newNoopLogger() *noopLogger {
 	return new(noopLogger)
 }
 
-func (l *noopLogger) Debug(string)             {}
-func (l *noopLogger) Info(string)              {}
-func (l *noopLogger) Warn(string)              {}
-func (l *noopLogger) Error(string)             {}
-func (l *noopLogger) PatchLevel(logging.Level) {}
-func (l *noopLogger) PatchPrefix(string)       {}
+func (l *noopLogger) Debug(s string)                 {}
+func (l *noopLogger) Info(s string)                  {}
+func (l *noopLogger) Warn(s string)                  {}
+func (l *noopLogger) Error(s string)                 {}
+func (l *noopLogger) PatchLevel(level logging.Level) {}
+func (l *noopLogger) PatchPrefix(prefix string)      {}

internal/cli/openvpnconfig.go

@@ -3,11 +3,12 @@ package cli
 import (
 	"context"
 	"fmt"
+	"net"
 	"net/http"
-	"net/netip"
 	"strings"
 	"time"
 
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/openvpn/extract"
 	"github.com/qdm12/gluetun/internal/provider"
@@ -28,19 +29,14 @@ type Unzipper interface {
 
 type ParallelResolver interface {
 	Resolve(ctx context.Context, settings resolver.ParallelSettings) (
-		hostToIPs map[string][]netip.Addr, warnings []string, err error)
+		hostToIPs map[string][]net.IP, warnings []string, err error)
 }
 
 type IPFetcher interface {
-	FetchMultiInfo(ctx context.Context, ips []netip.Addr) (data []ipinfo.Response, err error)
+	FetchMultiInfo(ctx context.Context, ips []net.IP) (data []ipinfo.Response, err error)
 }
 
-type IPv6Checker interface {
-	IsIPv6Supported() (supported bool, err error)
-}
-
-func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, source Source,
-	ipv6Checker IPv6Checker) error {
+func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, source sources.Source) error {
 	storage, err := storage.New(logger, constants.ServersData)
 	if err != nil {
 		return err
@@ -51,13 +47,8 @@ func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, source Source,
 		return err
 	}
 
-	ipv6Supported, err := ipv6Checker.IsIPv6Supported()
-	if err != nil {
-		return fmt.Errorf("checking for IPv6 support: %w", err)
-	}
-
-	if err = allSettings.Validate(storage, ipv6Supported); err != nil {
-		return fmt.Errorf("validating settings: %w", err)
+	if err = allSettings.Validate(storage); err != nil {
+		return err
 	}
 
 	// Unused by this CLI command
@@ -71,14 +62,12 @@ func (c *CLI) OpenvpnConfig(logger OpenvpnConfigLogger, source Source,
 	providers := provider.NewProviders(storage, time.Now, warner, client,
 		unzipper, parallelResolver, ipFetcher, openvpnFileExtractor)
 	providerConf := providers.Get(*allSettings.VPN.Provider.Name)
-	connection, err := providerConf.GetConnection(
-		allSettings.VPN.Provider.ServerSelection, ipv6Supported)
+	connection, err := providerConf.GetConnection(allSettings.VPN.Provider.ServerSelection)
 	if err != nil {
 		return err
 	}
 
-	lines := providerConf.OpenVPNConfig(connection,
-		allSettings.VPN.OpenVPN, ipv6Supported)
+	lines := providerConf.OpenVPNConfig(connection, allSettings.VPN.OpenVPN)
 
 	fmt.Println(strings.Join(lines, "\n"))
 	return nil

internal/cli/update.go

@@ -51,14 +51,14 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	}
 
 	if !endUserMode && !maintainerMode {
-		return fmt.Errorf("%w", ErrModeUnspecified)
+		return ErrModeUnspecified
 	}
 
 	if updateAll {
 		options.Providers = providers.All()
 	} else {
 		if csvProviders == "" {
-			return fmt.Errorf("%w", ErrNoProviderSpecified)
+			return ErrNoProviderSpecified
 		}
 		options.Providers = strings.Split(csvProviders, ",")
 	}
@@ -72,7 +72,7 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 
 	storage, err := storage.New(logger, constants.ServersData)
 	if err != nil {
-		return fmt.Errorf("creating servers storage: %w", err)
+		return fmt.Errorf("cannot create servers storage: %w", err)
 	}
 
 	const clientTimeout = 10 * time.Second
@@ -88,13 +88,13 @@ func (c *CLI) Update(ctx context.Context, args []string, logger UpdaterLogger) e
 	updater := updater.New(httpClient, storage, providers, logger)
 	err = updater.UpdateServers(ctx, options.Providers, options.MinRatio)
 	if err != nil {
-		return fmt.Errorf("updating server information: %w", err)
+		return fmt.Errorf("cannot update server information: %w", err)
 	}
 
 	if maintainerMode {
 		err := storage.FlushToFile(c.repoServersPath)
 		if err != nil {
-			return fmt.Errorf("writing servers data to embedded JSON file: %w", err)
+			return fmt.Errorf("cannot write servers data to embedded JSON file: %w", err)
 		}
 	}
 

internal/configuration/settings/dns.go

@@ -2,7 +2,7 @@ package settings
 
 import (
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
@@ -13,9 +13,9 @@ type DNS struct {
 	// ServerAddress is the DNS server to use inside
 	// the Go program and for the system.
 	// It defaults to '127.0.0.1' to be used with the
-	// DoT server. It cannot be the zero value in the internal
+	// DoT server. It cannot be nil in the internal
 	// state.
-	ServerAddress netip.Addr
+	ServerAddress net.IP
 	// KeepNameserver is true if the Docker DNS server
 	// found in /etc/resolv.conf should be kept.
 	// Note settings this to true will go around the
@@ -31,7 +31,7 @@ type DNS struct {
 func (d DNS) validate() (err error) {
 	err = d.DoT.validate()
 	if err != nil {
-		return fmt.Errorf("validating DoT settings: %w", err)
+		return fmt.Errorf("failed validating DoT settings: %w", err)
 	}
 
 	return nil
@@ -39,8 +39,8 @@ func (d DNS) validate() (err error) {
 
 func (d *DNS) Copy() (copied DNS) {
 	return DNS{
-		ServerAddress:  d.ServerAddress,
-		KeepNameserver: helpers.CopyPointer(d.KeepNameserver),
+		ServerAddress:  helpers.CopyIP(d.ServerAddress),
+		KeepNameserver: helpers.CopyBoolPtr(d.KeepNameserver),
 		DoT:            d.DoT.copy(),
 	}
 }
@@ -49,7 +49,7 @@ func (d *DNS) Copy() (copied DNS) {
 // unset field of the receiver settings object.
 func (d *DNS) mergeWith(other DNS) {
 	d.ServerAddress = helpers.MergeWithIP(d.ServerAddress, other.ServerAddress)
-	d.KeepNameserver = helpers.MergeWithPointer(d.KeepNameserver, other.KeepNameserver)
+	d.KeepNameserver = helpers.MergeWithBool(d.KeepNameserver, other.KeepNameserver)
 	d.DoT.mergeWith(other.DoT)
 }
 
@@ -58,14 +58,14 @@ func (d *DNS) mergeWith(other DNS) {
 // settings.
 func (d *DNS) overrideWith(other DNS) {
 	d.ServerAddress = helpers.OverrideWithIP(d.ServerAddress, other.ServerAddress)
-	d.KeepNameserver = helpers.OverrideWithPointer(d.KeepNameserver, other.KeepNameserver)
+	d.KeepNameserver = helpers.OverrideWithBool(d.KeepNameserver, other.KeepNameserver)
 	d.DoT.overrideWith(other.DoT)
 }
 
 func (d *DNS) setDefaults() {
-	localhost := netip.AddrFrom4([4]byte{127, 0, 0, 1})
+	localhost := net.IPv4(127, 0, 0, 1) //nolint:gomnd
 	d.ServerAddress = helpers.DefaultIP(d.ServerAddress, localhost)
-	d.KeepNameserver = helpers.DefaultPointer(d.KeepNameserver, false)
+	d.KeepNameserver = helpers.DefaultBool(d.KeepNameserver, false)
 	d.DoT.setDefaults()
 }
 

internal/configuration/settings/dnsblacklist.go

@@ -3,12 +3,12 @@ package settings
 import (
 	"errors"
 	"fmt"
-	"net/netip"
 	"regexp"
 
 	"github.com/qdm12/dns/pkg/blacklist"
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
+	"inet.af/netaddr"
 )
 
 // DNSBlacklist is settings for the DNS blacklist building.
@@ -18,14 +18,14 @@ type DNSBlacklist struct {
 	BlockSurveillance    *bool
 	AllowedHosts         []string
 	AddBlockedHosts      []string
-	AddBlockedIPs        []netip.Addr
-	AddBlockedIPPrefixes []netip.Prefix
+	AddBlockedIPs        []netaddr.IP
+	AddBlockedIPPrefixes []netaddr.IPPrefix
 }
 
 func (b *DNSBlacklist) setDefaults() {
-	b.BlockMalicious = helpers.DefaultPointer(b.BlockMalicious, true)
-	b.BlockAds = helpers.DefaultPointer(b.BlockAds, false)
-	b.BlockSurveillance = helpers.DefaultPointer(b.BlockSurveillance, true)
+	b.BlockMalicious = helpers.DefaultBool(b.BlockMalicious, true)
+	b.BlockAds = helpers.DefaultBool(b.BlockAds, false)
+	b.BlockSurveillance = helpers.DefaultBool(b.BlockSurveillance, true)
 }
 
 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
@@ -53,34 +53,34 @@ func (b DNSBlacklist) validate() (err error) {
 
 func (b DNSBlacklist) copy() (copied DNSBlacklist) {
 	return DNSBlacklist{
-		BlockMalicious:       helpers.CopyPointer(b.BlockMalicious),
-		BlockAds:             helpers.CopyPointer(b.BlockAds),
-		BlockSurveillance:    helpers.CopyPointer(b.BlockSurveillance),
-		AllowedHosts:         helpers.CopySlice(b.AllowedHosts),
-		AddBlockedHosts:      helpers.CopySlice(b.AddBlockedHosts),
-		AddBlockedIPs:        helpers.CopySlice(b.AddBlockedIPs),
-		AddBlockedIPPrefixes: helpers.CopySlice(b.AddBlockedIPPrefixes),
+		BlockMalicious:       helpers.CopyBoolPtr(b.BlockMalicious),
+		BlockAds:             helpers.CopyBoolPtr(b.BlockAds),
+		BlockSurveillance:    helpers.CopyBoolPtr(b.BlockSurveillance),
+		AllowedHosts:         helpers.CopyStringSlice(b.AllowedHosts),
+		AddBlockedHosts:      helpers.CopyStringSlice(b.AddBlockedHosts),
+		AddBlockedIPs:        helpers.CopyNetaddrIPsSlice(b.AddBlockedIPs),
+		AddBlockedIPPrefixes: helpers.CopyIPPrefixSlice(b.AddBlockedIPPrefixes),
 	}
 }
 
 func (b *DNSBlacklist) mergeWith(other DNSBlacklist) {
-	b.BlockMalicious = helpers.MergeWithPointer(b.BlockMalicious, other.BlockMalicious)
-	b.BlockAds = helpers.MergeWithPointer(b.BlockAds, other.BlockAds)
-	b.BlockSurveillance = helpers.MergeWithPointer(b.BlockSurveillance, other.BlockSurveillance)
-	b.AllowedHosts = helpers.MergeSlices(b.AllowedHosts, other.AllowedHosts)
-	b.AddBlockedHosts = helpers.MergeSlices(b.AddBlockedHosts, other.AddBlockedHosts)
-	b.AddBlockedIPs = helpers.MergeSlices(b.AddBlockedIPs, other.AddBlockedIPs)
-	b.AddBlockedIPPrefixes = helpers.MergeSlices(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
+	b.BlockMalicious = helpers.MergeWithBool(b.BlockMalicious, other.BlockMalicious)
+	b.BlockAds = helpers.MergeWithBool(b.BlockAds, other.BlockAds)
+	b.BlockSurveillance = helpers.MergeWithBool(b.BlockSurveillance, other.BlockSurveillance)
+	b.AllowedHosts = helpers.MergeStringSlices(b.AllowedHosts, other.AllowedHosts)
+	b.AddBlockedHosts = helpers.MergeStringSlices(b.AddBlockedHosts, other.AddBlockedHosts)
+	b.AddBlockedIPs = helpers.MergeNetaddrIPsSlices(b.AddBlockedIPs, other.AddBlockedIPs)
+	b.AddBlockedIPPrefixes = helpers.MergeIPPrefixesSlices(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
 }
 
 func (b *DNSBlacklist) overrideWith(other DNSBlacklist) {
-	b.BlockMalicious = helpers.OverrideWithPointer(b.BlockMalicious, other.BlockMalicious)
-	b.BlockAds = helpers.OverrideWithPointer(b.BlockAds, other.BlockAds)
-	b.BlockSurveillance = helpers.OverrideWithPointer(b.BlockSurveillance, other.BlockSurveillance)
-	b.AllowedHosts = helpers.OverrideWithSlice(b.AllowedHosts, other.AllowedHosts)
-	b.AddBlockedHosts = helpers.OverrideWithSlice(b.AddBlockedHosts, other.AddBlockedHosts)
-	b.AddBlockedIPs = helpers.OverrideWithSlice(b.AddBlockedIPs, other.AddBlockedIPs)
-	b.AddBlockedIPPrefixes = helpers.OverrideWithSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
+	b.BlockMalicious = helpers.OverrideWithBool(b.BlockMalicious, other.BlockMalicious)
+	b.BlockAds = helpers.OverrideWithBool(b.BlockAds, other.BlockAds)
+	b.BlockSurveillance = helpers.OverrideWithBool(b.BlockSurveillance, other.BlockSurveillance)
+	b.AllowedHosts = helpers.OverrideWithStringSlice(b.AllowedHosts, other.AllowedHosts)
+	b.AddBlockedHosts = helpers.OverrideWithStringSlice(b.AddBlockedHosts, other.AddBlockedHosts)
+	b.AddBlockedIPs = helpers.OverrideWithNetaddrIPsSlice(b.AddBlockedIPs, other.AddBlockedIPs)
+	b.AddBlockedIPPrefixes = helpers.OverrideWithIPPrefixesSlice(b.AddBlockedIPPrefixes, other.AddBlockedIPPrefixes)
 }
 
 func (b DNSBlacklist) ToBlacklistFormat() (settings blacklist.BuilderSettings, err error) {
@@ -90,8 +90,8 @@ func (b DNSBlacklist) ToBlacklistFormat() (settings blacklist.BuilderSettings, e
 		BlockSurveillance:    *b.BlockSurveillance,
 		AllowedHosts:         b.AllowedHosts,
 		AddBlockedHosts:      b.AddBlockedHosts,
-		AddBlockedIPs:        netipAddressesToNetaddrIPs(b.AddBlockedIPs),
-		AddBlockedIPPrefixes: netipPrefixesToNetaddrIPPrefixes(b.AddBlockedIPPrefixes),
+		AddBlockedIPs:        b.AddBlockedIPs,
+		AddBlockedIPPrefixes: b.AddBlockedIPPrefixes,
 	}, nil
 }
 

internal/configuration/settings/dot.go

@@ -54,8 +54,8 @@ func (d DoT) validate() (err error) {
 
 func (d *DoT) copy() (copied DoT) {
 	return DoT{
-		Enabled:      helpers.CopyPointer(d.Enabled),
-		UpdatePeriod: helpers.CopyPointer(d.UpdatePeriod),
+		Enabled:      helpers.CopyBoolPtr(d.Enabled),
+		UpdatePeriod: helpers.CopyDurationPtr(d.UpdatePeriod),
 		Unbound:      d.Unbound.copy(),
 		Blacklist:    d.Blacklist.copy(),
 	}
@@ -64,8 +64,8 @@ func (d *DoT) copy() (copied DoT) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (d *DoT) mergeWith(other DoT) {
-	d.Enabled = helpers.MergeWithPointer(d.Enabled, other.Enabled)
-	d.UpdatePeriod = helpers.MergeWithPointer(d.UpdatePeriod, other.UpdatePeriod)
+	d.Enabled = helpers.MergeWithBool(d.Enabled, other.Enabled)
+	d.UpdatePeriod = helpers.MergeWithDurationPtr(d.UpdatePeriod, other.UpdatePeriod)
 	d.Unbound.mergeWith(other.Unbound)
 	d.Blacklist.mergeWith(other.Blacklist)
 }
@@ -74,16 +74,16 @@ func (d *DoT) mergeWith(other DoT) {
 // settings object with any field set in the other
 // settings.
 func (d *DoT) overrideWith(other DoT) {
-	d.Enabled = helpers.OverrideWithPointer(d.Enabled, other.Enabled)
-	d.UpdatePeriod = helpers.OverrideWithPointer(d.UpdatePeriod, other.UpdatePeriod)
+	d.Enabled = helpers.OverrideWithBool(d.Enabled, other.Enabled)
+	d.UpdatePeriod = helpers.OverrideWithDurationPtr(d.UpdatePeriod, other.UpdatePeriod)
 	d.Unbound.overrideWith(other.Unbound)
 	d.Blacklist.overrideWith(other.Blacklist)
 }
 
 func (d *DoT) setDefaults() {
-	d.Enabled = helpers.DefaultPointer(d.Enabled, true)
+	d.Enabled = helpers.DefaultBool(d.Enabled, true)
 	const defaultUpdatePeriod = 24 * time.Hour
-	d.UpdatePeriod = helpers.DefaultPointer(d.UpdatePeriod, defaultUpdatePeriod)
+	d.UpdatePeriod = helpers.DefaultDurationPtr(d.UpdatePeriod, defaultUpdatePeriod)
 	d.Unbound.setDefaults()
 	d.Blacklist.setDefaults()
 }

internal/configuration/settings/errors.go

@@ -37,13 +37,10 @@ var (
 	ErrWireguardEndpointIPNotSet       = errors.New("endpoint IP is not set")
 	ErrWireguardEndpointPortNotAllowed = errors.New("endpoint port is not allowed")
 	ErrWireguardEndpointPortNotSet     = errors.New("endpoint port is not set")
-	ErrWireguardEndpointPortSet        = errors.New("endpoint port is set")
 	ErrWireguardInterfaceAddressNotSet = errors.New("interface address is not set")
-	ErrWireguardInterfaceAddressIPv6   = errors.New("interface address is IPv6 but IPv6 is not supported")
 	ErrWireguardInterfaceNotValid      = errors.New("interface name is not valid")
 	ErrWireguardPreSharedKeyNotSet     = errors.New("pre-shared key is not set")
 	ErrWireguardPrivateKeyNotSet       = errors.New("private key is not set")
 	ErrWireguardPublicKeyNotSet        = errors.New("public key is not set")
 	ErrWireguardPublicKeyNotValid      = errors.New("public key is not valid")
-	ErrWireguardImplementationNotValid = errors.New("implementation is not valid")
 )

internal/configuration/settings/firewall.go

@@ -2,7 +2,7 @@ package settings
 
 import (
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
@@ -12,7 +12,7 @@ import (
 type Firewall struct {
 	VPNInputPorts   []uint16
 	InputPorts      []uint16
-	OutboundSubnets []netip.Prefix
+	OutboundSubnets []net.IPNet
 	Enabled         *bool
 	Debug           *bool
 }
@@ -40,11 +40,11 @@ func hasZeroPort(ports []uint16) (has bool) {
 
 func (f *Firewall) copy() (copied Firewall) {
 	return Firewall{
-		VPNInputPorts:   helpers.CopySlice(f.VPNInputPorts),
-		InputPorts:      helpers.CopySlice(f.InputPorts),
-		OutboundSubnets: helpers.CopySlice(f.OutboundSubnets),
-		Enabled:         helpers.CopyPointer(f.Enabled),
-		Debug:           helpers.CopyPointer(f.Debug),
+		VPNInputPorts:   helpers.CopyUint16Slice(f.VPNInputPorts),
+		InputPorts:      helpers.CopyUint16Slice(f.InputPorts),
+		OutboundSubnets: helpers.CopyIPNetSlice(f.OutboundSubnets),
+		Enabled:         helpers.CopyBoolPtr(f.Enabled),
+		Debug:           helpers.CopyBoolPtr(f.Debug),
 	}
 }
 
@@ -53,27 +53,27 @@ func (f *Firewall) copy() (copied Firewall) {
 // It merges values of slices together, even if they
 // are set in the receiver settings.
 func (f *Firewall) mergeWith(other Firewall) {
-	f.VPNInputPorts = helpers.MergeSlices(f.VPNInputPorts, other.VPNInputPorts)
-	f.InputPorts = helpers.MergeSlices(f.InputPorts, other.InputPorts)
-	f.OutboundSubnets = helpers.MergeSlices(f.OutboundSubnets, other.OutboundSubnets)
-	f.Enabled = helpers.MergeWithPointer(f.Enabled, other.Enabled)
-	f.Debug = helpers.MergeWithPointer(f.Debug, other.Debug)
+	f.VPNInputPorts = helpers.MergeUint16Slices(f.VPNInputPorts, other.VPNInputPorts)
+	f.InputPorts = helpers.MergeUint16Slices(f.InputPorts, other.InputPorts)
+	f.OutboundSubnets = helpers.MergeIPNetsSlices(f.OutboundSubnets, other.OutboundSubnets)
+	f.Enabled = helpers.MergeWithBool(f.Enabled, other.Enabled)
+	f.Debug = helpers.MergeWithBool(f.Debug, other.Debug)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (f *Firewall) overrideWith(other Firewall) {
-	f.VPNInputPorts = helpers.OverrideWithSlice(f.VPNInputPorts, other.VPNInputPorts)
-	f.InputPorts = helpers.OverrideWithSlice(f.InputPorts, other.InputPorts)
-	f.OutboundSubnets = helpers.OverrideWithSlice(f.OutboundSubnets, other.OutboundSubnets)
-	f.Enabled = helpers.OverrideWithPointer(f.Enabled, other.Enabled)
-	f.Debug = helpers.OverrideWithPointer(f.Debug, other.Debug)
+	f.VPNInputPorts = helpers.OverrideWithUint16Slice(f.VPNInputPorts, other.VPNInputPorts)
+	f.InputPorts = helpers.OverrideWithUint16Slice(f.InputPorts, other.InputPorts)
+	f.OutboundSubnets = helpers.OverrideWithIPNetsSlice(f.OutboundSubnets, other.OutboundSubnets)
+	f.Enabled = helpers.OverrideWithBool(f.Enabled, other.Enabled)
+	f.Debug = helpers.OverrideWithBool(f.Debug, other.Debug)
 }
 
 func (f *Firewall) setDefaults() {
-	f.Enabled = helpers.DefaultPointer(f.Enabled, true)
-	f.Debug = helpers.DefaultPointer(f.Debug, false)
+	f.Enabled = helpers.DefaultBool(f.Enabled, true)
+	f.Debug = helpers.DefaultBool(f.Debug, false)
 }
 
 func (f Firewall) String() string {
@@ -109,8 +109,7 @@ func (f Firewall) toLinesNode() (node *gotree.Node) {
 	if len(f.OutboundSubnets) > 0 {
 		outboundSubnets := node.Appendf("Outbound subnets:")
 		for _, subnet := range f.OutboundSubnets {
-			subnet := subnet
-			outboundSubnets.Appendf("%s", &subnet)
+			outboundSubnets.Appendf("%s", subnet)
 		}
 	}
 

internal/configuration/settings/health.go

@@ -20,19 +20,13 @@ type Health struct {
 	// 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.
+	//  HTTP server. It defaults to 500 milliseconds.
 	ReadTimeout time.Duration
 	// TargetAddress is the address (host or host:port)
 	// to TCP dial to periodically for the health check.
 	// It cannot be the empty string in the internal state.
 	TargetAddress string
-	// SuccessWait is the duration to wait to re-run the
-	// healthcheck after a successful healthcheck.
-	// It defaults to 5 seconds and cannot be zero in
-	// the internal state.
-	SuccessWait time.Duration
-	// VPN has health settings specific to the VPN loop.
-	VPN HealthyWait
+	VPN           HealthyWait
 }
 
 func (h Health) Validate() (err error) {
@@ -57,7 +51,6 @@ func (h *Health) copy() (copied Health) {
 		ReadHeaderTimeout: h.ReadHeaderTimeout,
 		ReadTimeout:       h.ReadTimeout,
 		TargetAddress:     h.TargetAddress,
-		SuccessWait:       h.SuccessWait,
 		VPN:               h.VPN.copy(),
 	}
 }
@@ -66,10 +59,9 @@ func (h *Health) copy() (copied Health) {
 // unset field of the receiver settings object.
 func (h *Health) MergeWith(other Health) {
 	h.ServerAddress = helpers.MergeWithString(h.ServerAddress, other.ServerAddress)
-	h.ReadHeaderTimeout = helpers.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = helpers.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.ReadHeaderTimeout = helpers.MergeWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.MergeWithDuration(h.ReadTimeout, other.ReadTimeout)
 	h.TargetAddress = helpers.MergeWithString(h.TargetAddress, other.TargetAddress)
-	h.SuccessWait = helpers.MergeWithNumber(h.SuccessWait, other.SuccessWait)
 	h.VPN.mergeWith(other.VPN)
 }
 
@@ -78,22 +70,19 @@ func (h *Health) MergeWith(other Health) {
 // settings.
 func (h *Health) OverrideWith(other Health) {
 	h.ServerAddress = helpers.OverrideWithString(h.ServerAddress, other.ServerAddress)
-	h.ReadHeaderTimeout = helpers.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = helpers.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.ReadHeaderTimeout = helpers.OverrideWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.OverrideWithDuration(h.ReadTimeout, other.ReadTimeout)
 	h.TargetAddress = helpers.OverrideWithString(h.TargetAddress, other.TargetAddress)
-	h.SuccessWait = helpers.OverrideWithNumber(h.SuccessWait, other.SuccessWait)
 	h.VPN.overrideWith(other.VPN)
 }
 
 func (h *Health) SetDefaults() {
 	h.ServerAddress = helpers.DefaultString(h.ServerAddress, "127.0.0.1:9999")
 	const defaultReadHeaderTimeout = 100 * time.Millisecond
-	h.ReadHeaderTimeout = helpers.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
+	h.ReadHeaderTimeout = helpers.DefaultDuration(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
 	const defaultReadTimeout = 500 * time.Millisecond
-	h.ReadTimeout = helpers.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
+	h.ReadTimeout = helpers.DefaultDuration(h.ReadTimeout, defaultReadTimeout)
 	h.TargetAddress = helpers.DefaultString(h.TargetAddress, "cloudflare.com:443")
-	const defaultSuccessWait = 5 * time.Second
-	h.SuccessWait = helpers.DefaultNumber(h.SuccessWait, defaultSuccessWait)
 	h.VPN.setDefaults()
 }
 
@@ -105,7 +94,6 @@ func (h Health) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Health settings:")
 	node.Appendf("Server listening address: %s", h.ServerAddress)
 	node.Appendf("Target address: %s", h.TargetAddress)
-	node.Appendf("Duration to wait after success: %s", h.SuccessWait)
 	node.Appendf("Read header timeout: %s", h.ReadHeaderTimeout)
 	node.Appendf("Read timeout: %s", h.ReadTimeout)
 	node.AppendNode(h.VPN.toLinesNode("VPN"))

internal/configuration/settings/healthywait.go

@@ -27,31 +27,31 @@ func (h HealthyWait) validate() (err error) {
 // unset field of the receiver settings object.
 func (h *HealthyWait) copy() (copied HealthyWait) {
 	return HealthyWait{
-		Initial:  helpers.CopyPointer(h.Initial),
-		Addition: helpers.CopyPointer(h.Addition),
+		Initial:  helpers.CopyDurationPtr(h.Initial),
+		Addition: helpers.CopyDurationPtr(h.Addition),
 	}
 }
 
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (h *HealthyWait) mergeWith(other HealthyWait) {
-	h.Initial = helpers.MergeWithPointer(h.Initial, other.Initial)
-	h.Addition = helpers.MergeWithPointer(h.Addition, other.Addition)
+	h.Initial = helpers.MergeWithDurationPtr(h.Initial, other.Initial)
+	h.Addition = helpers.MergeWithDurationPtr(h.Addition, other.Addition)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (h *HealthyWait) overrideWith(other HealthyWait) {
-	h.Initial = helpers.OverrideWithPointer(h.Initial, other.Initial)
-	h.Addition = helpers.OverrideWithPointer(h.Addition, other.Addition)
+	h.Initial = helpers.OverrideWithDurationPtr(h.Initial, other.Initial)
+	h.Addition = helpers.OverrideWithDurationPtr(h.Addition, other.Addition)
 }
 
 func (h *HealthyWait) setDefaults() {
 	const initialDurationDefault = 6 * time.Second
 	const additionDurationDefault = 5 * time.Second
-	h.Initial = helpers.DefaultPointer(h.Initial, initialDurationDefault)
-	h.Addition = helpers.DefaultPointer(h.Addition, additionDurationDefault)
+	h.Initial = helpers.DefaultDurationPtr(h.Initial, initialDurationDefault)
+	h.Addition = helpers.DefaultDurationPtr(h.Addition, additionDurationDefault)
 }
 
 func (h HealthyWait) String() string {

internal/configuration/settings/helpers/belong.go

@@ -22,7 +22,7 @@ var (
 
 func AreAllOneOf(values, choices []string) (err error) {
 	if len(values) > 0 && len(choices) == 0 {
-		return fmt.Errorf("%w", ErrNoChoice)
+		return ErrNoChoice
 	}
 
 	set := make(map[string]struct{}, len(choices))

internal/configuration/settings/helpers/copy.go

@@ -1,20 +1,199 @@
 package helpers
 
 import (
-	"net/netip"
+	"net"
+	"time"
 
-	"golang.org/x/exp/slices"
+	"github.com/qdm12/log"
+	"inet.af/netaddr"
 )
 
-func CopyPointer[T any](original *T) (copied *T) {
+func CopyStringPtr(original *string) (copied *string) {
 	if original == nil {
 		return nil
 	}
-	copied = new(T)
+	copied = new(string)
 	*copied = *original
 	return copied
 }
 
-func CopySlice[T string | uint16 | netip.Addr | netip.Prefix](original []T) (copied []T) {
-	return slices.Clone(original)
+func CopyBoolPtr(original *bool) (copied *bool) {
+	if original == nil {
+		return nil
+	}
+	copied = new(bool)
+	*copied = *original
+	return copied
+}
+
+func CopyUint8Ptr(original *uint8) (copied *uint8) {
+	if original == nil {
+		return nil
+	}
+	copied = new(uint8)
+	*copied = *original
+	return copied
+}
+
+func CopyUint16Ptr(original *uint16) (copied *uint16) {
+	if original == nil {
+		return nil
+	}
+	copied = new(uint16)
+	*copied = *original
+	return copied
+}
+
+func CopyUint32Ptr(original *uint32) (copied *uint32) {
+	if original == nil {
+		return nil
+	}
+	copied = new(uint32)
+	*copied = *original
+	return copied
+}
+
+func CopyIntPtr(original *int) (copied *int) {
+	if original == nil {
+		return nil
+	}
+	copied = new(int)
+	*copied = *original
+	return copied
+}
+
+func CopyDurationPtr(original *time.Duration) (copied *time.Duration) {
+	if original == nil {
+		return nil
+	}
+	copied = new(time.Duration)
+	*copied = *original
+	return copied
+}
+
+func CopyLogLevelPtr(original *log.Level) (copied *log.Level) {
+	if original == nil {
+		return nil
+	}
+	copied = new(log.Level)
+	*copied = *original
+	return copied
+}
+
+func CopyIP(original net.IP) (copied net.IP) {
+	if original == nil {
+		return nil
+	}
+	copied = make(net.IP, len(original))
+	copy(copied, original)
+	return copied
+}
+
+func CopyIPNet(original net.IPNet) (copied net.IPNet) {
+	if original.IP != nil {
+		copied.IP = make(net.IP, len(original.IP))
+		copy(copied.IP, original.IP)
+	}
+
+	if original.Mask != nil {
+		copied.Mask = make(net.IPMask, len(original.Mask))
+		copy(copied.Mask, original.Mask)
+	}
+
+	return copied
+}
+
+func CopyIPNetPtr(original *net.IPNet) (copied *net.IPNet) {
+	if original == nil {
+		return nil
+	}
+
+	copied = new(net.IPNet)
+	*copied = CopyIPNet(*original)
+	return copied
+}
+
+func CopyNetaddrIP(original netaddr.IP) (copied netaddr.IP) {
+	b, err := original.MarshalBinary()
+	if err != nil {
+		panic(err)
+	}
+
+	err = copied.UnmarshalBinary(b)
+	if err != nil {
+		panic(err)
+	}
+
+	return copied
+}
+
+func CopyIPPrefix(original netaddr.IPPrefix) (copied netaddr.IPPrefix) {
+	b, err := original.MarshalText()
+	if err != nil {
+		panic(err)
+	}
+
+	err = copied.UnmarshalText(b)
+	if err != nil {
+		panic(err)
+	}
+
+	return copied
+}
+
+func CopyStringSlice(original []string) (copied []string) {
+	if original == nil {
+		return nil
+	}
+
+	copied = make([]string, len(original))
+	copy(copied, original)
+	return copied
+}
+
+func CopyUint16Slice(original []uint16) (copied []uint16) {
+	if original == nil {
+		return nil
+	}
+
+	copied = make([]uint16, len(original))
+	copy(copied, original)
+	return copied
+}
+
+func CopyIPNetSlice(original []net.IPNet) (copied []net.IPNet) {
+	if original == nil {
+		return nil
+	}
+
+	copied = make([]net.IPNet, len(original))
+	for i := range original {
+		copied[i] = CopyIPNet(original[i])
+	}
+	return copied
+}
+
+func CopyIPPrefixSlice(original []netaddr.IPPrefix) (copied []netaddr.IPPrefix) {
+	if original == nil {
+		return nil
+	}
+
+	copied = make([]netaddr.IPPrefix, len(original))
+	for i := range original {
+		copied[i] = CopyIPPrefix(original[i])
+	}
+	return copied
+}
+
+func CopyNetaddrIPsSlice(original []netaddr.IP) (copied []netaddr.IP) {
+	if original == nil {
+		return nil
+	}
+
+	copied = make([]netaddr.IP, len(original))
+	for i := range original {
+		copied[i] = CopyNetaddrIP(original[i])
+	}
+
+	return copied
 }

internal/configuration/settings/helpers/default.go

@@ -1,15 +1,57 @@
 package helpers
 
 import (
-	"net/netip"
+	"net"
+	"time"
+
+	"github.com/qdm12/log"
 )
 
-func DefaultPointer[T any](existing *T, defaultValue T) (
-	result *T) {
+func DefaultInt(existing *int, defaultValue int) (
+	result *int) {
 	if existing != nil {
 		return existing
 	}
-	result = new(T)
+	result = new(int)
+	*result = defaultValue
+	return result
+}
+
+func DefaultUint8(existing *uint8, defaultValue uint8) (
+	result *uint8) {
+	if existing != nil {
+		return existing
+	}
+	result = new(uint8)
+	*result = defaultValue
+	return result
+}
+
+func DefaultUint16(existing *uint16, defaultValue uint16) (
+	result *uint16) {
+	if existing != nil {
+		return existing
+	}
+	result = new(uint16)
+	*result = defaultValue
+	return result
+}
+func DefaultUint32(existing *uint32, defaultValue uint32) (
+	result *uint32) {
+	if existing != nil {
+		return existing
+	}
+	result = new(uint32)
+	*result = defaultValue
+	return result
+}
+
+func DefaultBool(existing *bool, defaultValue bool) (
+	result *bool) {
+	if existing != nil {
+		return existing
+	}
+	result = new(bool)
 	*result = defaultValue
 	return result
 }
@@ -22,17 +64,46 @@ func DefaultString(existing string, defaultValue string) (
 	return defaultValue
 }
 
-func DefaultNumber[T Number](existing T, defaultValue T) ( //nolint:ireturn
-	result T) {
+func DefaultStringPtr(existing *string, defaultValue string) (result *string) {
+	if existing != nil {
+		return existing
+	}
+	result = new(string)
+	*result = defaultValue
+	return result
+}
+
+func DefaultDuration(existing time.Duration,
+	defaultValue time.Duration) (result time.Duration) {
 	if existing != 0 {
 		return existing
 	}
 	return defaultValue
 }
 
-func DefaultIP(existing netip.Addr, defaultValue netip.Addr) (
-	result netip.Addr) {
-	if existing.IsValid() {
+func DefaultDurationPtr(existing *time.Duration,
+	defaultValue time.Duration) (result *time.Duration) {
+	if existing != nil {
+		return existing
+	}
+	result = new(time.Duration)
+	*result = defaultValue
+	return result
+}
+
+func DefaultLogLevel(existing *log.Level,
+	defaultValue log.Level) (result *log.Level) {
+	if existing != nil {
+		return existing
+	}
+	result = new(log.Level)
+	*result = defaultValue
+	return result
+}
+
+func DefaultIP(existing net.IP, defaultValue net.IP) (
+	result net.IP) {
+	if existing != nil {
 		return existing
 	}
 	return defaultValue

internal/configuration/settings/helpers/generics.go

@@ -1,10 +0,0 @@
-package helpers
-
-import "time"
-
-type Number interface {
-	uint8 | uint16 | uint32 | uint64 | uint |
-		int8 | int16 | int32 | int64 | int |
-		float32 | float64 |
-		time.Duration
-}

internal/configuration/settings/helpers/merge.go

@@ -1,17 +1,21 @@
 package helpers
 
 import (
+	"net"
 	"net/http"
-	"net/netip"
+	"time"
+
+	"github.com/qdm12/log"
+	"inet.af/netaddr"
 )
 
-func MergeWithPointer[T any](existing, other *T) (result *T) {
+func MergeWithBool(existing, other *bool) (result *bool) {
 	if existing != nil {
 		return existing
 	} else if other == nil {
 		return nil
 	}
-	result = new(T)
+	result = new(bool)
 	*result = *other
 	return result
 }
@@ -23,20 +27,111 @@ func MergeWithString(existing, other string) (result string) {
 	return other
 }
 
-func MergeWithNumber[T Number](existing, other T) (result T) { //nolint:ireturn
+func MergeWithInt(existing, other int) (result int) {
 	if existing != 0 {
 		return existing
 	}
 	return other
 }
 
-func MergeWithIP(existing, other netip.Addr) (result netip.Addr) {
-	if existing.IsValid() {
+func MergeWithFloat64(existing, other float64) (result float64) {
+	if existing != 0 {
 		return existing
 	}
 	return other
 }
 
+func MergeWithStringPtr(existing, other *string) (result *string) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(string)
+	*result = *other
+	return result
+}
+
+func MergeWithIntPtr(existing, other *int) (result *int) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(int)
+	*result = *other
+	return result
+}
+
+func MergeWithUint8(existing, other *uint8) (result *uint8) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(uint8)
+	*result = *other
+	return result
+}
+
+func MergeWithUint16(existing, other *uint16) (result *uint16) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(uint16)
+	*result = *other
+	return result
+}
+
+func MergeWithUint32(existing, other *uint32) (result *uint32) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(uint32)
+	*result = *other
+	return result
+}
+
+func MergeWithIP(existing, other net.IP) (result net.IP) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = make(net.IP, len(other))
+	copy(result, other)
+	return result
+}
+
+func MergeWithDuration(existing, other time.Duration) (result time.Duration) {
+	if existing != 0 {
+		return existing
+	}
+	return other
+}
+
+func MergeWithDurationPtr(existing, other *time.Duration) (result *time.Duration) {
+	if existing != nil {
+		return existing
+	}
+	return other
+}
+
+func MergeWithLogLevel(existing, other *log.Level) (result *log.Level) {
+	if existing != nil {
+		return existing
+	} else if other == nil {
+		return nil
+	}
+	result = new(log.Level)
+	*result = *other
+	return result
+}
+
 func MergeWithHTTPHandler(existing, other http.Handler) (result http.Handler) {
 	if existing != nil {
 		return existing
@@ -44,13 +139,13 @@ func MergeWithHTTPHandler(existing, other http.Handler) (result http.Handler) {
 	return other
 }
 
-func MergeSlices[T comparable](a, b []T) (result []T) {
+func MergeStringSlices(a, b []string) (result []string) {
 	if a == nil && b == nil {
 		return nil
 	}
 
-	seen := make(map[T]struct{}, len(a)+len(b))
-	result = make([]T, 0, len(a)+len(b))
+	seen := make(map[string]struct{}, len(a)+len(b))
+	result = make([]string, 0, len(a)+len(b))
 	for _, s := range a {
 		if _, ok := seen[s]; ok {
 			continue // duplicate
@@ -67,3 +162,105 @@ func MergeSlices[T comparable](a, b []T) (result []T) {
 	}
 	return result
 }
+
+func MergeUint16Slices(a, b []uint16) (result []uint16) {
+	if a == nil && b == nil {
+		return nil
+	}
+
+	seen := make(map[uint16]struct{}, len(a)+len(b))
+	result = make([]uint16, 0, len(a)+len(b))
+	for _, n := range a {
+		if _, ok := seen[n]; ok {
+			continue // duplicate
+		}
+		result = append(result, n)
+		seen[n] = struct{}{}
+	}
+	for _, n := range b {
+		if _, ok := seen[n]; ok {
+			continue // duplicate
+		}
+		result = append(result, n)
+		seen[n] = struct{}{}
+	}
+	return result
+}
+
+func MergeIPNetsSlices(a, b []net.IPNet) (result []net.IPNet) {
+	if a == nil && b == nil {
+		return nil
+	}
+
+	seen := make(map[string]struct{}, len(a)+len(b))
+	result = make([]net.IPNet, 0, len(a)+len(b))
+	for _, ipNet := range a {
+		key := ipNet.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ipNet)
+		seen[key] = struct{}{}
+	}
+	for _, ipNet := range b {
+		key := ipNet.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ipNet)
+		seen[key] = struct{}{}
+	}
+	return result
+}
+
+func MergeNetaddrIPsSlices(a, b []netaddr.IP) (result []netaddr.IP) {
+	if a == nil && b == nil {
+		return nil
+	}
+
+	seen := make(map[string]struct{}, len(a)+len(b))
+	result = make([]netaddr.IP, 0, len(a)+len(b))
+	for _, ip := range a {
+		key := ip.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ip)
+		seen[key] = struct{}{}
+	}
+	for _, ip := range b {
+		key := ip.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ip)
+		seen[key] = struct{}{}
+	}
+	return result
+}
+
+func MergeIPPrefixesSlices(a, b []netaddr.IPPrefix) (result []netaddr.IPPrefix) {
+	if a == nil && b == nil {
+		return nil
+	}
+
+	seen := make(map[string]struct{}, len(a)+len(b))
+	result = make([]netaddr.IPPrefix, 0, len(a)+len(b))
+	for _, ipPrefix := range a {
+		key := ipPrefix.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ipPrefix)
+		seen[key] = struct{}{}
+	}
+	for _, ipPrefix := range b {
+		key := ipPrefix.String()
+		if _, ok := seen[key]; ok {
+			continue // duplicate
+		}
+		result = append(result, ipPrefix)
+		seen[key] = struct{}{}
+	}
+	return result
+}

internal/configuration/settings/helpers/override.go

@@ -1,15 +1,19 @@
 package helpers
 
 import (
+	"net"
 	"net/http"
-	"net/netip"
+	"time"
+
+	"github.com/qdm12/log"
+	"inet.af/netaddr"
 )
 
-func OverrideWithPointer[T any](existing, other *T) (result *T) {
+func OverrideWithBool(existing, other *bool) (result *bool) {
 	if other == nil {
 		return existing
 	}
-	result = new(T)
+	result = new(bool)
 	*result = *other
 	return result
 }
@@ -21,20 +25,101 @@ func OverrideWithString(existing, other string) (result string) {
 	return other
 }
 
-func OverrideWithNumber[T Number](existing, other T) (result T) { //nolint:ireturn
+func OverrideWithInt(existing, other int) (result int) {
 	if other == 0 {
 		return existing
 	}
 	return other
 }
 
-func OverrideWithIP(existing, other netip.Addr) (result netip.Addr) {
-	if !other.IsValid() {
+func OverrideWithFloat64(existing, other float64) (result float64) {
+	if other == 0 {
 		return existing
 	}
 	return other
 }
 
+func OverrideWithStringPtr(existing, other *string) (result *string) {
+	if other == nil {
+		return existing
+	}
+	result = new(string)
+	*result = *other
+	return result
+}
+
+func OverrideWithIntPtr(existing, other *int) (result *int) {
+	if other == nil {
+		return existing
+	}
+	result = new(int)
+	*result = *other
+	return result
+}
+
+func OverrideWithUint8(existing, other *uint8) (result *uint8) {
+	if other == nil {
+		return existing
+	}
+	result = new(uint8)
+	*result = *other
+	return result
+}
+
+func OverrideWithUint16(existing, other *uint16) (result *uint16) {
+	if other == nil {
+		return existing
+	}
+	result = new(uint16)
+	*result = *other
+	return result
+}
+
+func OverrideWithUint32(existing, other *uint32) (result *uint32) {
+	if other == nil {
+		return existing
+	}
+	result = new(uint32)
+	*result = *other
+	return result
+}
+
+func OverrideWithIP(existing, other net.IP) (result net.IP) {
+	if other == nil {
+		return existing
+	}
+	result = make(net.IP, len(other))
+	copy(result, other)
+	return result
+}
+
+func OverrideWithDuration(existing, other time.Duration) (
+	result time.Duration) {
+	if other == 0 {
+		return existing
+	}
+	return other
+}
+
+func OverrideWithDurationPtr(existing, other *time.Duration) (
+	result *time.Duration) {
+	if other == nil {
+		return existing
+	}
+	result = new(time.Duration)
+	*result = *other
+	return result
+}
+
+func OverrideWithLogLevel(existing, other *log.Level) (result *log.Level) {
+	if other == nil {
+		return existing
+	}
+	result = new(log.Level)
+	*result = *other
+	return result
+}
+
 func OverrideWithHTTPHandler(existing, other http.Handler) (result http.Handler) {
 	if other != nil {
 		return other
@@ -42,11 +127,47 @@ func OverrideWithHTTPHandler(existing, other http.Handler) (result http.Handler)
 	return existing
 }
 
-func OverrideWithSlice[T any](existing, other []T) (result []T) {
+func OverrideWithStringSlice(existing, other []string) (result []string) {
 	if other == nil {
 		return existing
 	}
-	result = make([]T, len(other))
+	result = make([]string, len(other))
+	copy(result, other)
+	return result
+}
+
+func OverrideWithUint16Slice(existing, other []uint16) (result []uint16) {
+	if other == nil {
+		return existing
+	}
+	result = make([]uint16, len(other))
+	copy(result, other)
+	return result
+}
+
+func OverrideWithIPNetsSlice(existing, other []net.IPNet) (result []net.IPNet) {
+	if other == nil {
+		return existing
+	}
+	result = make([]net.IPNet, len(other))
+	copy(result, other)
+	return result
+}
+
+func OverrideWithNetaddrIPsSlice(existing, other []netaddr.IP) (result []netaddr.IP) {
+	if other == nil {
+		return existing
+	}
+	result = make([]netaddr.IP, len(other))
+	copy(result, other)
+	return result
+}
+
+func OverrideWithIPPrefixesSlice(existing, other []netaddr.IPPrefix) (result []netaddr.IPPrefix) {
+	if other == nil {
+		return existing
+	}
+	result = make([]netaddr.IPPrefix, len(other))
 	copy(result, other)
 	return result
 }

internal/configuration/settings/helpers/pointers.go

@@ -0,0 +1,11 @@
+package helpers
+
+import "time"
+
+// StringPtr returns a pointer to the string value
+// passed as argument.
+func StringPtr(s string) *string { return &s }
+
+// DurationPtr returns a pointer to the duration value
+// passed as argument.
+func DurationPtr(d time.Duration) *time.Duration { return &d }

internal/configuration/settings/httpproxy.go

@@ -56,12 +56,12 @@ func (h HTTPProxy) validate() (err error) {
 
 func (h *HTTPProxy) copy() (copied HTTPProxy) {
 	return HTTPProxy{
-		User:              helpers.CopyPointer(h.User),
-		Password:          helpers.CopyPointer(h.Password),
+		User:              helpers.CopyStringPtr(h.User),
+		Password:          helpers.CopyStringPtr(h.Password),
 		ListeningAddress:  h.ListeningAddress,
-		Enabled:           helpers.CopyPointer(h.Enabled),
-		Stealth:           helpers.CopyPointer(h.Stealth),
-		Log:               helpers.CopyPointer(h.Log),
+		Enabled:           helpers.CopyBoolPtr(h.Enabled),
+		Stealth:           helpers.CopyBoolPtr(h.Stealth),
+		Log:               helpers.CopyBoolPtr(h.Log),
 		ReadHeaderTimeout: h.ReadHeaderTimeout,
 		ReadTimeout:       h.ReadTimeout,
 	}
@@ -70,41 +70,41 @@ func (h *HTTPProxy) copy() (copied HTTPProxy) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (h *HTTPProxy) mergeWith(other HTTPProxy) {
-	h.User = helpers.MergeWithPointer(h.User, other.User)
-	h.Password = helpers.MergeWithPointer(h.Password, other.Password)
+	h.User = helpers.MergeWithStringPtr(h.User, other.User)
+	h.Password = helpers.MergeWithStringPtr(h.Password, other.Password)
 	h.ListeningAddress = helpers.MergeWithString(h.ListeningAddress, other.ListeningAddress)
-	h.Enabled = helpers.MergeWithPointer(h.Enabled, other.Enabled)
-	h.Stealth = helpers.MergeWithPointer(h.Stealth, other.Stealth)
-	h.Log = helpers.MergeWithPointer(h.Log, other.Log)
-	h.ReadHeaderTimeout = helpers.MergeWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = helpers.MergeWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.Enabled = helpers.MergeWithBool(h.Enabled, other.Enabled)
+	h.Stealth = helpers.MergeWithBool(h.Stealth, other.Stealth)
+	h.Log = helpers.MergeWithBool(h.Log, other.Log)
+	h.ReadHeaderTimeout = helpers.MergeWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.MergeWithDuration(h.ReadTimeout, other.ReadTimeout)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (h *HTTPProxy) overrideWith(other HTTPProxy) {
-	h.User = helpers.OverrideWithPointer(h.User, other.User)
-	h.Password = helpers.OverrideWithPointer(h.Password, other.Password)
+	h.User = helpers.OverrideWithStringPtr(h.User, other.User)
+	h.Password = helpers.OverrideWithStringPtr(h.Password, other.Password)
 	h.ListeningAddress = helpers.OverrideWithString(h.ListeningAddress, other.ListeningAddress)
-	h.Enabled = helpers.OverrideWithPointer(h.Enabled, other.Enabled)
-	h.Stealth = helpers.OverrideWithPointer(h.Stealth, other.Stealth)
-	h.Log = helpers.OverrideWithPointer(h.Log, other.Log)
-	h.ReadHeaderTimeout = helpers.OverrideWithNumber(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
-	h.ReadTimeout = helpers.OverrideWithNumber(h.ReadTimeout, other.ReadTimeout)
+	h.Enabled = helpers.OverrideWithBool(h.Enabled, other.Enabled)
+	h.Stealth = helpers.OverrideWithBool(h.Stealth, other.Stealth)
+	h.Log = helpers.OverrideWithBool(h.Log, other.Log)
+	h.ReadHeaderTimeout = helpers.OverrideWithDuration(h.ReadHeaderTimeout, other.ReadHeaderTimeout)
+	h.ReadTimeout = helpers.OverrideWithDuration(h.ReadTimeout, other.ReadTimeout)
 }
 
 func (h *HTTPProxy) setDefaults() {
-	h.User = helpers.DefaultPointer(h.User, "")
-	h.Password = helpers.DefaultPointer(h.Password, "")
+	h.User = helpers.DefaultStringPtr(h.User, "")
+	h.Password = helpers.DefaultStringPtr(h.Password, "")
 	h.ListeningAddress = helpers.DefaultString(h.ListeningAddress, ":8888")
-	h.Enabled = helpers.DefaultPointer(h.Enabled, false)
-	h.Stealth = helpers.DefaultPointer(h.Stealth, false)
-	h.Log = helpers.DefaultPointer(h.Log, false)
+	h.Enabled = helpers.DefaultBool(h.Enabled, false)
+	h.Stealth = helpers.DefaultBool(h.Stealth, false)
+	h.Log = helpers.DefaultBool(h.Log, false)
 	const defaultReadHeaderTimeout = time.Second
-	h.ReadHeaderTimeout = helpers.DefaultNumber(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
+	h.ReadHeaderTimeout = helpers.DefaultDuration(h.ReadHeaderTimeout, defaultReadHeaderTimeout)
 	const defaultReadTimeout = 3 * time.Second
-	h.ReadTimeout = helpers.DefaultNumber(h.ReadTimeout, defaultReadTimeout)
+	h.ReadTimeout = helpers.DefaultDuration(h.ReadTimeout, defaultReadTimeout)
 }
 
 func (h HTTPProxy) String() string {

internal/configuration/settings/log.go

@@ -19,25 +19,25 @@ func (l Log) validate() (err error) {
 
 func (l *Log) copy() (copied Log) {
 	return Log{
-		Level: helpers.CopyPointer(l.Level),
+		Level: helpers.CopyLogLevelPtr(l.Level),
 	}
 }
 
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (l *Log) mergeWith(other Log) {
-	l.Level = helpers.MergeWithPointer(l.Level, other.Level)
+	l.Level = helpers.MergeWithLogLevel(l.Level, other.Level)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (l *Log) overrideWith(other Log) {
-	l.Level = helpers.OverrideWithPointer(l.Level, other.Level)
+	l.Level = helpers.OverrideWithLogLevel(l.Level, other.Level)
 }
 
 func (l *Log) setDefaults() {
-	l.Level = helpers.DefaultPointer(l.Level, log.LevelInfo)
+	l.Level = helpers.DefaultLogLevel(l.Level, log.LevelInfo)
 }
 
 func (l Log) String() string {

internal/configuration/settings/netaddr.go

@@ -1,36 +0,0 @@
-package settings
-
-import (
-	"net/netip"
-
-	"inet.af/netaddr"
-)
-
-func netipAddressToNetaddrIP(address netip.Addr) (ip netaddr.IP) {
-	if address.Is4() {
-		return netaddr.IPFrom4(address.As4())
-	}
-	return netaddr.IPFrom16(address.As16())
-}
-
-func netipAddressesToNetaddrIPs(addresses []netip.Addr) (ips []netaddr.IP) {
-	ips = make([]netaddr.IP, len(addresses))
-	for i := range addresses {
-		ips[i] = netipAddressToNetaddrIP(addresses[i])
-	}
-	return ips
-}
-
-func netipPrefixToNetaddrIPPrefix(prefix netip.Prefix) (ipPrefix netaddr.IPPrefix) {
-	netaddrIP := netipAddressToNetaddrIP(prefix.Addr())
-	bits := prefix.Bits()
-	return netaddr.IPPrefixFrom(netaddrIP, uint8(bits))
-}
-
-func netipPrefixesToNetaddrIPPrefixes(prefixes []netip.Prefix) (ipPrefixes []netaddr.IPPrefix) {
-	ipPrefixes = make([]netaddr.IPPrefix, len(prefixes))
-	for i := range ipPrefixes {
-		ipPrefixes[i] = netipPrefixToNetaddrIPPrefix(prefixes[i])
-	}
-	return ipPrefixes
-}

internal/configuration/settings/openvpn.go

@@ -42,18 +42,18 @@ type OpenVPN struct {
 	// It cannot be nil in the internal state.
 	// It is ignored if it is set to the empty string.
 	Auth *string
-	// Cert is the base64 encoded DER of an OpenVPN certificate for the <cert> block.
+	// Cert is the OpenVPN certificate for the <cert> block.
 	// This is notably used by Cyberghost and VPN secure.
 	// It can be set to the empty string to be ignored.
 	// It cannot be nil in the internal state.
 	Cert *string
-	// Key is the base64 encoded DER of an OpenVPN key.
+	// Key is the OpenVPN key.
 	// This is used by Cyberghost and VPN Unlimited.
 	// It can be set to the empty string to be ignored.
 	// It cannot be nil in the internal state.
 	Key *string
-	// EncryptedKey is the base64 encoded DER of an encrypted key for OpenVPN.
-	// It is used by VPN secure.
+	// EncryptedKey is the content of an encrypted
+	// key for OpenVPN. It is used by VPN secure.
 	// It defaults to the empty string meaning it is not
 	// to be used. KeyPassphrase must be set if this one is set.
 	EncryptedKey *string
@@ -65,6 +65,10 @@ type OpenVPN struct {
 	// Private Internet Access. It can be set to an
 	// empty string for other providers.
 	PIAEncPreset *string
+	// IPv6 is set to true if IPv6 routing should be
+	// set to be tunnel in OpenVPN, and false otherwise.
+	// It cannot be nil in the internal state.
+	IPv6 *bool // TODO automate like with Wireguard
 	// MSSFix is the value (1 to 10000) to set for the
 	// mssfix option for OpenVPN. It is ignored if set to 0.
 	// It cannot be nil in the internal state.
@@ -95,19 +99,17 @@ func (o OpenVPN) validate(vpnProvider string) (err error) {
 	}
 
 	isCustom := vpnProvider == providers.Custom
-	isUserRequired := !isCustom &&
-		vpnProvider != providers.Airvpn &&
-		vpnProvider != providers.VPNSecure
+	isUserRequired := !isCustom && vpnProvider != providers.VPNSecure
 
 	if isUserRequired && *o.User == "" {
-		return fmt.Errorf("%w", ErrOpenVPNUserIsEmpty)
+		return ErrOpenVPNUserIsEmpty
 	}
 
 	passwordRequired := isUserRequired &&
 		(vpnProvider != providers.Ivpn || !ivpnAccountID.MatchString(*o.User))
 
 	if passwordRequired && *o.Password == "" {
-		return fmt.Errorf("%w", ErrOpenVPNPasswordIsEmpty)
+		return ErrOpenVPNPasswordIsEmpty
 	}
 
 	err = validateOpenVPNConfigFilepath(isCustom, *o.ConfFile)
@@ -160,7 +162,7 @@ func validateOpenVPNConfigFilepath(isCustom bool,
 	}
 
 	if confFile == "" {
-		return fmt.Errorf("%w", ErrFilepathMissing)
+		return ErrFilepathMissing
 	}
 
 	err = helpers.FileExists(confFile)
@@ -171,7 +173,7 @@ func validateOpenVPNConfigFilepath(isCustom bool,
 	extractor := extract.New()
 	_, _, err = extractor.Data(confFile)
 	if err != nil {
-		return fmt.Errorf("extracting information from custom configuration file: %w", err)
+		return fmt.Errorf("failed extracting information from custom configuration file: %w", err)
 	}
 
 	return nil
@@ -181,12 +183,11 @@ func validateOpenVPNClientCertificate(vpnProvider,
 	clientCert string) (err error) {
 	switch vpnProvider {
 	case
-		providers.Airvpn,
 		providers.Cyberghost,
 		providers.VPNSecure,
 		providers.VPNUnlimited:
 		if clientCert == "" {
-			return fmt.Errorf("%w", ErrMissingValue)
+			return ErrMissingValue
 		}
 	}
 
@@ -204,12 +205,11 @@ func validateOpenVPNClientCertificate(vpnProvider,
 func validateOpenVPNClientKey(vpnProvider, clientKey string) (err error) {
 	switch vpnProvider {
 	case
-		providers.Airvpn,
 		providers.Cyberghost,
 		providers.VPNUnlimited,
 		providers.Wevpn:
 		if clientKey == "" {
-			return fmt.Errorf("%w", ErrMissingValue)
+			return ErrMissingValue
 		}
 	}
 
@@ -227,7 +227,7 @@ func validateOpenVPNClientKey(vpnProvider, clientKey string) (err error) {
 func validateOpenVPNEncryptedKey(vpnProvider,
 	encryptedPrivateKey string) (err error) {
 	if vpnProvider == providers.VPNSecure && encryptedPrivateKey == "" {
-		return fmt.Errorf("%w", ErrMissingValue)
+		return ErrMissingValue
 	}
 
 	if encryptedPrivateKey == "" {
@@ -244,21 +244,22 @@ func validateOpenVPNEncryptedKey(vpnProvider,
 func (o *OpenVPN) copy() (copied OpenVPN) {
 	return OpenVPN{
 		Version:       o.Version,
-		User:          helpers.CopyPointer(o.User),
-		Password:      helpers.CopyPointer(o.Password),
-		ConfFile:      helpers.CopyPointer(o.ConfFile),
-		Ciphers:       helpers.CopySlice(o.Ciphers),
-		Auth:          helpers.CopyPointer(o.Auth),
-		Cert:          helpers.CopyPointer(o.Cert),
-		Key:           helpers.CopyPointer(o.Key),
-		EncryptedKey:  helpers.CopyPointer(o.EncryptedKey),
-		KeyPassphrase: helpers.CopyPointer(o.KeyPassphrase),
-		PIAEncPreset:  helpers.CopyPointer(o.PIAEncPreset),
-		MSSFix:        helpers.CopyPointer(o.MSSFix),
+		User:          helpers.CopyStringPtr(o.User),
+		Password:      helpers.CopyStringPtr(o.Password),
+		ConfFile:      helpers.CopyStringPtr(o.ConfFile),
+		Ciphers:       helpers.CopyStringSlice(o.Ciphers),
+		Auth:          helpers.CopyStringPtr(o.Auth),
+		Cert:          helpers.CopyStringPtr(o.Cert),
+		Key:           helpers.CopyStringPtr(o.Key),
+		EncryptedKey:  helpers.CopyStringPtr(o.EncryptedKey),
+		KeyPassphrase: helpers.CopyStringPtr(o.KeyPassphrase),
+		PIAEncPreset:  helpers.CopyStringPtr(o.PIAEncPreset),
+		IPv6:          helpers.CopyBoolPtr(o.IPv6),
+		MSSFix:        helpers.CopyUint16Ptr(o.MSSFix),
 		Interface:     o.Interface,
 		ProcessUser:   o.ProcessUser,
-		Verbosity:     helpers.CopyPointer(o.Verbosity),
-		Flags:         helpers.CopySlice(o.Flags),
+		Verbosity:     helpers.CopyIntPtr(o.Verbosity),
+		Flags:         helpers.CopyStringSlice(o.Flags),
 	}
 }
 
@@ -266,21 +267,22 @@ func (o *OpenVPN) copy() (copied OpenVPN) {
 // unset field of the receiver settings object.
 func (o *OpenVPN) mergeWith(other OpenVPN) {
 	o.Version = helpers.MergeWithString(o.Version, other.Version)
-	o.User = helpers.MergeWithPointer(o.User, other.User)
-	o.Password = helpers.MergeWithPointer(o.Password, other.Password)
-	o.ConfFile = helpers.MergeWithPointer(o.ConfFile, other.ConfFile)
-	o.Ciphers = helpers.MergeSlices(o.Ciphers, other.Ciphers)
-	o.Auth = helpers.MergeWithPointer(o.Auth, other.Auth)
-	o.Cert = helpers.MergeWithPointer(o.Cert, other.Cert)
-	o.Key = helpers.MergeWithPointer(o.Key, other.Key)
-	o.EncryptedKey = helpers.MergeWithPointer(o.EncryptedKey, other.EncryptedKey)
-	o.KeyPassphrase = helpers.MergeWithPointer(o.KeyPassphrase, other.KeyPassphrase)
-	o.PIAEncPreset = helpers.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
-	o.MSSFix = helpers.MergeWithPointer(o.MSSFix, other.MSSFix)
+	o.User = helpers.MergeWithStringPtr(o.User, other.User)
+	o.Password = helpers.MergeWithStringPtr(o.Password, other.Password)
+	o.ConfFile = helpers.MergeWithStringPtr(o.ConfFile, other.ConfFile)
+	o.Ciphers = helpers.MergeStringSlices(o.Ciphers, other.Ciphers)
+	o.Auth = helpers.MergeWithStringPtr(o.Auth, other.Auth)
+	o.Cert = helpers.MergeWithStringPtr(o.Cert, other.Cert)
+	o.Key = helpers.MergeWithStringPtr(o.Key, other.Key)
+	o.EncryptedKey = helpers.MergeWithStringPtr(o.EncryptedKey, other.EncryptedKey)
+	o.KeyPassphrase = helpers.MergeWithStringPtr(o.KeyPassphrase, other.KeyPassphrase)
+	o.PIAEncPreset = helpers.MergeWithStringPtr(o.PIAEncPreset, other.PIAEncPreset)
+	o.IPv6 = helpers.MergeWithBool(o.IPv6, other.IPv6)
+	o.MSSFix = helpers.MergeWithUint16(o.MSSFix, other.MSSFix)
 	o.Interface = helpers.MergeWithString(o.Interface, other.Interface)
 	o.ProcessUser = helpers.MergeWithString(o.ProcessUser, other.ProcessUser)
-	o.Verbosity = helpers.MergeWithPointer(o.Verbosity, other.Verbosity)
-	o.Flags = helpers.MergeSlices(o.Flags, other.Flags)
+	o.Verbosity = helpers.MergeWithIntPtr(o.Verbosity, other.Verbosity)
+	o.Flags = helpers.MergeStringSlices(o.Flags, other.Flags)
 }
 
 // overrideWith overrides fields of the receiver
@@ -288,48 +290,51 @@ func (o *OpenVPN) mergeWith(other OpenVPN) {
 // settings.
 func (o *OpenVPN) overrideWith(other OpenVPN) {
 	o.Version = helpers.OverrideWithString(o.Version, other.Version)
-	o.User = helpers.OverrideWithPointer(o.User, other.User)
-	o.Password = helpers.OverrideWithPointer(o.Password, other.Password)
-	o.ConfFile = helpers.OverrideWithPointer(o.ConfFile, other.ConfFile)
-	o.Ciphers = helpers.OverrideWithSlice(o.Ciphers, other.Ciphers)
-	o.Auth = helpers.OverrideWithPointer(o.Auth, other.Auth)
-	o.Cert = helpers.OverrideWithPointer(o.Cert, other.Cert)
-	o.Key = helpers.OverrideWithPointer(o.Key, other.Key)
-	o.EncryptedKey = helpers.OverrideWithPointer(o.EncryptedKey, other.EncryptedKey)
-	o.KeyPassphrase = helpers.OverrideWithPointer(o.KeyPassphrase, other.KeyPassphrase)
-	o.PIAEncPreset = helpers.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
-	o.MSSFix = helpers.OverrideWithPointer(o.MSSFix, other.MSSFix)
+	o.User = helpers.OverrideWithStringPtr(o.User, other.User)
+	o.Password = helpers.OverrideWithStringPtr(o.Password, other.Password)
+	o.ConfFile = helpers.OverrideWithStringPtr(o.ConfFile, other.ConfFile)
+	o.Ciphers = helpers.OverrideWithStringSlice(o.Ciphers, other.Ciphers)
+	o.Auth = helpers.OverrideWithStringPtr(o.Auth, other.Auth)
+	o.Cert = helpers.OverrideWithStringPtr(o.Cert, other.Cert)
+	o.Key = helpers.OverrideWithStringPtr(o.Key, other.Key)
+	o.EncryptedKey = helpers.OverrideWithStringPtr(o.EncryptedKey, other.EncryptedKey)
+	o.KeyPassphrase = helpers.OverrideWithStringPtr(o.KeyPassphrase, other.KeyPassphrase)
+	o.PIAEncPreset = helpers.OverrideWithStringPtr(o.PIAEncPreset, other.PIAEncPreset)
+	o.IPv6 = helpers.OverrideWithBool(o.IPv6, other.IPv6)
+	o.MSSFix = helpers.OverrideWithUint16(o.MSSFix, other.MSSFix)
 	o.Interface = helpers.OverrideWithString(o.Interface, other.Interface)
 	o.ProcessUser = helpers.OverrideWithString(o.ProcessUser, other.ProcessUser)
-	o.Verbosity = helpers.OverrideWithPointer(o.Verbosity, other.Verbosity)
-	o.Flags = helpers.OverrideWithSlice(o.Flags, other.Flags)
+	o.Verbosity = helpers.OverrideWithIntPtr(o.Verbosity, other.Verbosity)
+	o.Flags = helpers.OverrideWithStringSlice(o.Flags, other.Flags)
 }
 
 func (o *OpenVPN) setDefaults(vpnProvider string) {
 	o.Version = helpers.DefaultString(o.Version, openvpn.Openvpn25)
-	o.User = helpers.DefaultPointer(o.User, "")
+	o.User = helpers.DefaultStringPtr(o.User, "")
 	if vpnProvider == providers.Mullvad {
-		o.Password = helpers.DefaultPointer(o.Password, "m")
+		o.Password = helpers.DefaultStringPtr(o.Password, "m")
 	} else {
-		o.Password = helpers.DefaultPointer(o.Password, "")
+		o.Password = helpers.DefaultStringPtr(o.Password, "")
 	}
 
-	o.ConfFile = helpers.DefaultPointer(o.ConfFile, "")
-	o.Auth = helpers.DefaultPointer(o.Auth, "")
-	o.Cert = helpers.DefaultPointer(o.Cert, "")
-	o.Key = helpers.DefaultPointer(o.Key, "")
-	o.EncryptedKey = helpers.DefaultPointer(o.EncryptedKey, "")
-	o.KeyPassphrase = helpers.DefaultPointer(o.KeyPassphrase, "")
+	o.ConfFile = helpers.DefaultStringPtr(o.ConfFile, "")
+	o.Auth = helpers.DefaultStringPtr(o.Auth, "")
+	o.Cert = helpers.DefaultStringPtr(o.Cert, "")
+	o.Key = helpers.DefaultStringPtr(o.Key, "")
+	o.EncryptedKey = helpers.DefaultStringPtr(o.EncryptedKey, "")
+	o.KeyPassphrase = helpers.DefaultStringPtr(o.KeyPassphrase, "")
 
 	var defaultEncPreset string
 	if vpnProvider == providers.PrivateInternetAccess {
 		defaultEncPreset = presets.Strong
 	}
-	o.PIAEncPreset = helpers.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
-	o.MSSFix = helpers.DefaultPointer(o.MSSFix, 0)
+	o.PIAEncPreset = helpers.DefaultStringPtr(o.PIAEncPreset, defaultEncPreset)
+
+	o.IPv6 = helpers.DefaultBool(o.IPv6, false)
+	o.MSSFix = helpers.DefaultUint16(o.MSSFix, 0)
 	o.Interface = helpers.DefaultString(o.Interface, "tun0")
 	o.ProcessUser = helpers.DefaultString(o.ProcessUser, "root")
-	o.Verbosity = helpers.DefaultPointer(o.Verbosity, 1)
+	o.Verbosity = helpers.DefaultInt(o.Verbosity, 1)
 }
 
 func (o OpenVPN) String() string {
@@ -371,6 +376,8 @@ func (o OpenVPN) toLinesNode() (node *gotree.Node) {
 		node.Appendf("Private Internet Access encryption preset: %s", *o.PIAEncPreset)
 	}
 
+	node.Appendf("Tunnel IPv6: %s", helpers.BoolPtrToYesNo(o.IPv6))
+
 	if *o.MSSFix > 0 {
 		node.Appendf("MSS Fix: %d", *o.MSSFix)
 	}

internal/configuration/settings/openvpnselection.go

@@ -67,12 +67,6 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 		default:
 			var allowedTCP, allowedUDP []uint16
 			switch vpnProvider {
-			case providers.Airvpn:
-				allowedTCP = []uint16{
-					53, 80, 443, // IP in 1, 3
-					1194, 2018, 41185, // IP in 1, 2, 3, 4
-				}
-				allowedUDP = []uint16{53, 80, 443, 1194, 2018, 41185}
 			case providers.Ivpn:
 				allowedTCP = []uint16{80, 443, 1143}
 				allowedUDP = []uint16{53, 1194, 2049, 2050}
@@ -130,37 +124,37 @@ func (o OpenVPNSelection) validate(vpnProvider string) (err error) {
 
 func (o *OpenVPNSelection) copy() (copied OpenVPNSelection) {
 	return OpenVPNSelection{
-		ConfFile:     helpers.CopyPointer(o.ConfFile),
-		TCP:          helpers.CopyPointer(o.TCP),
-		CustomPort:   helpers.CopyPointer(o.CustomPort),
-		PIAEncPreset: helpers.CopyPointer(o.PIAEncPreset),
+		ConfFile:     helpers.CopyStringPtr(o.ConfFile),
+		TCP:          helpers.CopyBoolPtr(o.TCP),
+		CustomPort:   helpers.CopyUint16Ptr(o.CustomPort),
+		PIAEncPreset: helpers.CopyStringPtr(o.PIAEncPreset),
 	}
 }
 
 func (o *OpenVPNSelection) mergeWith(other OpenVPNSelection) {
-	o.ConfFile = helpers.MergeWithPointer(o.ConfFile, other.ConfFile)
-	o.TCP = helpers.MergeWithPointer(o.TCP, other.TCP)
-	o.CustomPort = helpers.MergeWithPointer(o.CustomPort, other.CustomPort)
-	o.PIAEncPreset = helpers.MergeWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.ConfFile = helpers.MergeWithStringPtr(o.ConfFile, other.ConfFile)
+	o.TCP = helpers.MergeWithBool(o.TCP, other.TCP)
+	o.CustomPort = helpers.MergeWithUint16(o.CustomPort, other.CustomPort)
+	o.PIAEncPreset = helpers.MergeWithStringPtr(o.PIAEncPreset, other.PIAEncPreset)
 }
 
 func (o *OpenVPNSelection) overrideWith(other OpenVPNSelection) {
-	o.ConfFile = helpers.OverrideWithPointer(o.ConfFile, other.ConfFile)
-	o.TCP = helpers.OverrideWithPointer(o.TCP, other.TCP)
-	o.CustomPort = helpers.OverrideWithPointer(o.CustomPort, other.CustomPort)
-	o.PIAEncPreset = helpers.OverrideWithPointer(o.PIAEncPreset, other.PIAEncPreset)
+	o.ConfFile = helpers.OverrideWithStringPtr(o.ConfFile, other.ConfFile)
+	o.TCP = helpers.OverrideWithBool(o.TCP, other.TCP)
+	o.CustomPort = helpers.OverrideWithUint16(o.CustomPort, other.CustomPort)
+	o.PIAEncPreset = helpers.OverrideWithStringPtr(o.PIAEncPreset, other.PIAEncPreset)
 }
 
 func (o *OpenVPNSelection) setDefaults(vpnProvider string) {
-	o.ConfFile = helpers.DefaultPointer(o.ConfFile, "")
-	o.TCP = helpers.DefaultPointer(o.TCP, false)
-	o.CustomPort = helpers.DefaultPointer(o.CustomPort, 0)
+	o.ConfFile = helpers.DefaultStringPtr(o.ConfFile, "")
+	o.TCP = helpers.DefaultBool(o.TCP, false)
+	o.CustomPort = helpers.DefaultUint16(o.CustomPort, 0)
 
 	var defaultEncPreset string
 	if vpnProvider == providers.PrivateInternetAccess {
 		defaultEncPreset = presets.Strong
 	}
-	o.PIAEncPreset = helpers.DefaultPointer(o.PIAEncPreset, defaultEncPreset)
+	o.PIAEncPreset = helpers.DefaultStringPtr(o.PIAEncPreset, defaultEncPreset)
 }
 
 func (o OpenVPNSelection) String() string {

internal/configuration/settings/portforward.go

@@ -47,24 +47,24 @@ func (p PortForwarding) validate(vpnProvider string) (err error) {
 
 func (p *PortForwarding) copy() (copied PortForwarding) {
 	return PortForwarding{
-		Enabled:  helpers.CopyPointer(p.Enabled),
-		Filepath: helpers.CopyPointer(p.Filepath),
+		Enabled:  helpers.CopyBoolPtr(p.Enabled),
+		Filepath: helpers.CopyStringPtr(p.Filepath),
 	}
 }
 
 func (p *PortForwarding) mergeWith(other PortForwarding) {
-	p.Enabled = helpers.MergeWithPointer(p.Enabled, other.Enabled)
-	p.Filepath = helpers.MergeWithPointer(p.Filepath, other.Filepath)
+	p.Enabled = helpers.MergeWithBool(p.Enabled, other.Enabled)
+	p.Filepath = helpers.MergeWithStringPtr(p.Filepath, other.Filepath)
 }
 
 func (p *PortForwarding) overrideWith(other PortForwarding) {
-	p.Enabled = helpers.OverrideWithPointer(p.Enabled, other.Enabled)
-	p.Filepath = helpers.OverrideWithPointer(p.Filepath, other.Filepath)
+	p.Enabled = helpers.OverrideWithBool(p.Enabled, other.Enabled)
+	p.Filepath = helpers.OverrideWithStringPtr(p.Filepath, other.Filepath)
 }
 
 func (p *PortForwarding) setDefaults() {
-	p.Enabled = helpers.DefaultPointer(p.Enabled, false)
-	p.Filepath = helpers.DefaultPointer(p.Filepath, "/tmp/gluetun/forwarded_port")
+	p.Enabled = helpers.DefaultBool(p.Enabled, false)
+	p.Filepath = helpers.DefaultStringPtr(p.Filepath, "/tmp/gluetun/forwarded_port")
 }
 
 func (p PortForwarding) String() string {

internal/configuration/settings/provider.go

@@ -30,16 +30,14 @@ func (p *Provider) validate(vpnType string, storage Storage) (err error) {
 		validNames = append(validNames, "pia") // Retro-compatibility
 	} else { // Wireguard
 		validNames = []string{
-			providers.Airvpn,
 			providers.Custom,
 			providers.Ivpn,
 			providers.Mullvad,
-			providers.Surfshark,
 			providers.Windscribe,
 		}
 	}
 	if !helpers.IsOneOf(*p.Name, validNames...) {
-		return fmt.Errorf("%w for Wireguard: %q can only be one of %s",
+		return fmt.Errorf("%w: %q can only be one of %s",
 			ErrVPNProviderNameNotValid, *p.Name, helpers.ChoicesOrString(validNames))
 	}
 
@@ -58,26 +56,26 @@ func (p *Provider) validate(vpnType string, storage Storage) (err error) {
 
 func (p *Provider) copy() (copied Provider) {
 	return Provider{
-		Name:            helpers.CopyPointer(p.Name),
+		Name:            helpers.CopyStringPtr(p.Name),
 		ServerSelection: p.ServerSelection.copy(),
 		PortForwarding:  p.PortForwarding.copy(),
 	}
 }
 
 func (p *Provider) mergeWith(other Provider) {
-	p.Name = helpers.MergeWithPointer(p.Name, other.Name)
+	p.Name = helpers.MergeWithStringPtr(p.Name, other.Name)
 	p.ServerSelection.mergeWith(other.ServerSelection)
 	p.PortForwarding.mergeWith(other.PortForwarding)
 }
 
 func (p *Provider) overrideWith(other Provider) {
-	p.Name = helpers.OverrideWithPointer(p.Name, other.Name)
+	p.Name = helpers.OverrideWithStringPtr(p.Name, other.Name)
 	p.ServerSelection.overrideWith(other.ServerSelection)
 	p.PortForwarding.overrideWith(other.PortForwarding)
 }
 
 func (p *Provider) setDefaults() {
-	p.Name = helpers.DefaultPointer(p.Name, providers.PrivateInternetAccess)
+	p.Name = helpers.DefaultStringPtr(p.Name, providers.PrivateInternetAccess)
 	p.ServerSelection.setDefaults(*p.Name)
 	p.PortForwarding.setDefaults()
 }

internal/configuration/settings/publicip.go

@@ -42,25 +42,25 @@ func (p PublicIP) validate() (err error) {
 
 func (p *PublicIP) copy() (copied PublicIP) {
 	return PublicIP{
-		Period:     helpers.CopyPointer(p.Period),
-		IPFilepath: helpers.CopyPointer(p.IPFilepath),
+		Period:     helpers.CopyDurationPtr(p.Period),
+		IPFilepath: helpers.CopyStringPtr(p.IPFilepath),
 	}
 }
 
 func (p *PublicIP) mergeWith(other PublicIP) {
-	p.Period = helpers.MergeWithPointer(p.Period, other.Period)
-	p.IPFilepath = helpers.MergeWithPointer(p.IPFilepath, other.IPFilepath)
+	p.Period = helpers.MergeWithDurationPtr(p.Period, other.Period)
+	p.IPFilepath = helpers.MergeWithStringPtr(p.IPFilepath, other.IPFilepath)
 }
 
 func (p *PublicIP) overrideWith(other PublicIP) {
-	p.Period = helpers.OverrideWithPointer(p.Period, other.Period)
-	p.IPFilepath = helpers.OverrideWithPointer(p.IPFilepath, other.IPFilepath)
+	p.Period = helpers.OverrideWithDurationPtr(p.Period, other.Period)
+	p.IPFilepath = helpers.OverrideWithStringPtr(p.IPFilepath, other.IPFilepath)
 }
 
 func (p *PublicIP) setDefaults() {
 	const defaultPeriod = 12 * time.Hour
-	p.Period = helpers.DefaultPointer(p.Period, defaultPeriod)
-	p.IPFilepath = helpers.DefaultPointer(p.IPFilepath, "/tmp/gluetun/ip")
+	p.Period = helpers.DefaultDurationPtr(p.Period, defaultPeriod)
+	p.IPFilepath = helpers.DefaultStringPtr(p.IPFilepath, "/tmp/gluetun/ip")
 }
 
 func (p PublicIP) String() string {

internal/configuration/settings/server.go

@@ -43,29 +43,29 @@ func (c ControlServer) validate() (err error) {
 
 func (c *ControlServer) copy() (copied ControlServer) {
 	return ControlServer{
-		Address: helpers.CopyPointer(c.Address),
-		Log:     helpers.CopyPointer(c.Log),
+		Address: helpers.CopyStringPtr(c.Address),
+		Log:     helpers.CopyBoolPtr(c.Log),
 	}
 }
 
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (c *ControlServer) mergeWith(other ControlServer) {
-	c.Address = helpers.MergeWithPointer(c.Address, other.Address)
-	c.Log = helpers.MergeWithPointer(c.Log, other.Log)
+	c.Address = helpers.MergeWithStringPtr(c.Address, other.Address)
+	c.Log = helpers.MergeWithBool(c.Log, other.Log)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (c *ControlServer) overrideWith(other ControlServer) {
-	c.Address = helpers.OverrideWithPointer(c.Address, other.Address)
-	c.Log = helpers.OverrideWithPointer(c.Log, other.Log)
+	c.Address = helpers.OverrideWithStringPtr(c.Address, other.Address)
+	c.Log = helpers.OverrideWithBool(c.Log, other.Log)
 }
 
 func (c *ControlServer) setDefaults() {
-	c.Address = helpers.DefaultPointer(c.Address, ":8000")
-	c.Log = helpers.DefaultPointer(c.Log, true)
+	c.Address = helpers.DefaultStringPtr(c.Address, ":8000")
+	c.Log = helpers.DefaultBool(c.Log, true)
 }
 
 func (c ControlServer) String() string {

internal/configuration/settings/serverselection.go

@@ -3,7 +3,7 @@ package settings
 import (
 	"errors"
 	"fmt"
-	"net/netip"
+	"net"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
@@ -21,10 +21,10 @@ type ServerSelection struct { //nolint:maligned
 	VPN string
 	// TargetIP is the server endpoint IP address to use.
 	// It will override any IP address from the picked
-	// built-in server. It cannot be the empty value in the internal
-	// state, and can be set to the unspecified address to indicate
+	// built-in server. It cannot be nil in the internal
+	// state, and can be set to an empty net.IP{} to indicate
 	// there is not target IP address to use.
-	TargetIP netip.Addr
+	TargetIP net.IP
 	// Counties is the list of countries to filter VPN servers with.
 	Countries []string
 	// Regions is the list of regions to filter VPN servers with.
@@ -118,7 +118,7 @@ func (ss *ServerSelection) validate(vpnServiceProvider string,
 	}
 
 	if *ss.FreeOnly && *ss.PremiumOnly {
-		return fmt.Errorf("%w", ErrFreePremiumBothSet)
+		return ErrFreePremiumBothSet
 	}
 
 	if *ss.StreamOnly &&
@@ -202,19 +202,19 @@ func validateServerFilters(settings ServerSelection, filterChoices models.Filter
 func (ss *ServerSelection) copy() (copied ServerSelection) {
 	return ServerSelection{
 		VPN:          ss.VPN,
-		TargetIP:     ss.TargetIP,
-		Countries:    helpers.CopySlice(ss.Countries),
-		Regions:      helpers.CopySlice(ss.Regions),
-		Cities:       helpers.CopySlice(ss.Cities),
-		ISPs:         helpers.CopySlice(ss.ISPs),
-		Hostnames:    helpers.CopySlice(ss.Hostnames),
-		Names:        helpers.CopySlice(ss.Names),
-		Numbers:      helpers.CopySlice(ss.Numbers),
-		OwnedOnly:    helpers.CopyPointer(ss.OwnedOnly),
-		FreeOnly:     helpers.CopyPointer(ss.FreeOnly),
-		PremiumOnly:  helpers.CopyPointer(ss.PremiumOnly),
-		StreamOnly:   helpers.CopyPointer(ss.StreamOnly),
-		MultiHopOnly: helpers.CopyPointer(ss.MultiHopOnly),
+		TargetIP:     helpers.CopyIP(ss.TargetIP),
+		Countries:    helpers.CopyStringSlice(ss.Countries),
+		Regions:      helpers.CopyStringSlice(ss.Regions),
+		Cities:       helpers.CopyStringSlice(ss.Cities),
+		ISPs:         helpers.CopyStringSlice(ss.ISPs),
+		Hostnames:    helpers.CopyStringSlice(ss.Hostnames),
+		Names:        helpers.CopyStringSlice(ss.Names),
+		Numbers:      helpers.CopyUint16Slice(ss.Numbers),
+		OwnedOnly:    helpers.CopyBoolPtr(ss.OwnedOnly),
+		FreeOnly:     helpers.CopyBoolPtr(ss.FreeOnly),
+		PremiumOnly:  helpers.CopyBoolPtr(ss.PremiumOnly),
+		StreamOnly:   helpers.CopyBoolPtr(ss.StreamOnly),
+		MultiHopOnly: helpers.CopyBoolPtr(ss.MultiHopOnly),
 		OpenVPN:      ss.OpenVPN.copy(),
 		Wireguard:    ss.Wireguard.copy(),
 	}
@@ -223,18 +223,18 @@ func (ss *ServerSelection) copy() (copied ServerSelection) {
 func (ss *ServerSelection) mergeWith(other ServerSelection) {
 	ss.VPN = helpers.MergeWithString(ss.VPN, other.VPN)
 	ss.TargetIP = helpers.MergeWithIP(ss.TargetIP, other.TargetIP)
-	ss.Countries = helpers.MergeSlices(ss.Countries, other.Countries)
-	ss.Regions = helpers.MergeSlices(ss.Regions, other.Regions)
-	ss.Cities = helpers.MergeSlices(ss.Cities, other.Cities)
-	ss.ISPs = helpers.MergeSlices(ss.ISPs, other.ISPs)
-	ss.Hostnames = helpers.MergeSlices(ss.Hostnames, other.Hostnames)
-	ss.Names = helpers.MergeSlices(ss.Names, other.Names)
-	ss.Numbers = helpers.MergeSlices(ss.Numbers, other.Numbers)
-	ss.OwnedOnly = helpers.MergeWithPointer(ss.OwnedOnly, other.OwnedOnly)
-	ss.FreeOnly = helpers.MergeWithPointer(ss.FreeOnly, other.FreeOnly)
-	ss.PremiumOnly = helpers.MergeWithPointer(ss.PremiumOnly, other.PremiumOnly)
-	ss.StreamOnly = helpers.MergeWithPointer(ss.StreamOnly, other.StreamOnly)
-	ss.MultiHopOnly = helpers.MergeWithPointer(ss.MultiHopOnly, other.MultiHopOnly)
+	ss.Countries = helpers.MergeStringSlices(ss.Countries, other.Countries)
+	ss.Regions = helpers.MergeStringSlices(ss.Regions, other.Regions)
+	ss.Cities = helpers.MergeStringSlices(ss.Cities, other.Cities)
+	ss.ISPs = helpers.MergeStringSlices(ss.ISPs, other.ISPs)
+	ss.Hostnames = helpers.MergeStringSlices(ss.Hostnames, other.Hostnames)
+	ss.Names = helpers.MergeStringSlices(ss.Names, other.Names)
+	ss.Numbers = helpers.MergeUint16Slices(ss.Numbers, other.Numbers)
+	ss.OwnedOnly = helpers.MergeWithBool(ss.OwnedOnly, other.OwnedOnly)
+	ss.FreeOnly = helpers.MergeWithBool(ss.FreeOnly, other.FreeOnly)
+	ss.PremiumOnly = helpers.MergeWithBool(ss.PremiumOnly, other.PremiumOnly)
+	ss.StreamOnly = helpers.MergeWithBool(ss.StreamOnly, other.StreamOnly)
+	ss.MultiHopOnly = helpers.MergeWithBool(ss.MultiHopOnly, other.MultiHopOnly)
 
 	ss.OpenVPN.mergeWith(other.OpenVPN)
 	ss.Wireguard.mergeWith(other.Wireguard)
@@ -243,30 +243,30 @@ func (ss *ServerSelection) mergeWith(other ServerSelection) {
 func (ss *ServerSelection) overrideWith(other ServerSelection) {
 	ss.VPN = helpers.OverrideWithString(ss.VPN, other.VPN)
 	ss.TargetIP = helpers.OverrideWithIP(ss.TargetIP, other.TargetIP)
-	ss.Countries = helpers.OverrideWithSlice(ss.Countries, other.Countries)
-	ss.Regions = helpers.OverrideWithSlice(ss.Regions, other.Regions)
-	ss.Cities = helpers.OverrideWithSlice(ss.Cities, other.Cities)
-	ss.ISPs = helpers.OverrideWithSlice(ss.ISPs, other.ISPs)
-	ss.Hostnames = helpers.OverrideWithSlice(ss.Hostnames, other.Hostnames)
-	ss.Names = helpers.OverrideWithSlice(ss.Names, other.Names)
-	ss.Numbers = helpers.OverrideWithSlice(ss.Numbers, other.Numbers)
-	ss.OwnedOnly = helpers.OverrideWithPointer(ss.OwnedOnly, other.OwnedOnly)
-	ss.FreeOnly = helpers.OverrideWithPointer(ss.FreeOnly, other.FreeOnly)
-	ss.PremiumOnly = helpers.OverrideWithPointer(ss.PremiumOnly, other.PremiumOnly)
-	ss.StreamOnly = helpers.OverrideWithPointer(ss.StreamOnly, other.StreamOnly)
-	ss.MultiHopOnly = helpers.OverrideWithPointer(ss.MultiHopOnly, other.MultiHopOnly)
+	ss.Countries = helpers.OverrideWithStringSlice(ss.Countries, other.Countries)
+	ss.Regions = helpers.OverrideWithStringSlice(ss.Regions, other.Regions)
+	ss.Cities = helpers.OverrideWithStringSlice(ss.Cities, other.Cities)
+	ss.ISPs = helpers.OverrideWithStringSlice(ss.ISPs, other.ISPs)
+	ss.Hostnames = helpers.OverrideWithStringSlice(ss.Hostnames, other.Hostnames)
+	ss.Names = helpers.OverrideWithStringSlice(ss.Names, other.Names)
+	ss.Numbers = helpers.OverrideWithUint16Slice(ss.Numbers, other.Numbers)
+	ss.OwnedOnly = helpers.OverrideWithBool(ss.OwnedOnly, other.OwnedOnly)
+	ss.FreeOnly = helpers.OverrideWithBool(ss.FreeOnly, other.FreeOnly)
+	ss.PremiumOnly = helpers.OverrideWithBool(ss.PremiumOnly, other.PremiumOnly)
+	ss.StreamOnly = helpers.OverrideWithBool(ss.StreamOnly, other.StreamOnly)
+	ss.MultiHopOnly = helpers.OverrideWithBool(ss.MultiHopOnly, other.MultiHopOnly)
 	ss.OpenVPN.overrideWith(other.OpenVPN)
 	ss.Wireguard.overrideWith(other.Wireguard)
 }
 
 func (ss *ServerSelection) setDefaults(vpnProvider string) {
 	ss.VPN = helpers.DefaultString(ss.VPN, vpn.OpenVPN)
-	ss.TargetIP = helpers.DefaultIP(ss.TargetIP, netip.IPv4Unspecified())
-	ss.OwnedOnly = helpers.DefaultPointer(ss.OwnedOnly, false)
-	ss.FreeOnly = helpers.DefaultPointer(ss.FreeOnly, false)
-	ss.PremiumOnly = helpers.DefaultPointer(ss.PremiumOnly, false)
-	ss.StreamOnly = helpers.DefaultPointer(ss.StreamOnly, false)
-	ss.MultiHopOnly = helpers.DefaultPointer(ss.MultiHopOnly, false)
+	ss.TargetIP = helpers.DefaultIP(ss.TargetIP, net.IP{})
+	ss.OwnedOnly = helpers.DefaultBool(ss.OwnedOnly, false)
+	ss.FreeOnly = helpers.DefaultBool(ss.FreeOnly, false)
+	ss.PremiumOnly = helpers.DefaultBool(ss.PremiumOnly, false)
+	ss.StreamOnly = helpers.DefaultBool(ss.StreamOnly, false)
+	ss.MultiHopOnly = helpers.DefaultBool(ss.MultiHopOnly, false)
 	ss.OpenVPN.setDefaults(vpnProvider)
 	ss.Wireguard.setDefaults()
 }
@@ -278,7 +278,7 @@ func (ss ServerSelection) String() string {
 func (ss ServerSelection) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Server selection settings:")
 	node.Appendf("VPN type: %s", ss.VPN)
-	if !ss.TargetIP.IsUnspecified() {
+	if len(ss.TargetIP) > 0 {
 		node.Appendf("Target IP address: %s", ss.TargetIP)
 	}
 

internal/configuration/settings/settings.go

@@ -3,10 +3,6 @@ package settings
 import (
 	"fmt"
 
-	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
-	"github.com/qdm12/gluetun/internal/constants/openvpn"
-	"github.com/qdm12/gluetun/internal/constants/providers"
-	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/pprof"
 	"github.com/qdm12/gotree"
@@ -35,7 +31,7 @@ type Storage interface {
 // Validate validates all the settings and returns an error
 // if one of them is not valid.
 // TODO v4 remove pointer for receiver (because of Surfshark).
-func (s *Settings) Validate(storage Storage, ipv6Supported bool) (err error) {
+func (s *Settings) Validate(storage Storage) (err error) {
 	nameToValidation := map[string]func() error{
 		"control server":  s.ControlServer.validate,
 		"dns":             s.DNS.validate,
@@ -50,7 +46,7 @@ func (s *Settings) Validate(storage Storage, ipv6Supported bool) (err error) {
 		"version":         s.Version.validate,
 		// Pprof validation done in pprof constructor
 		"VPN": func() error {
-			return s.VPN.Validate(storage, ipv6Supported)
+			return s.VPN.Validate(storage)
 		},
 	}
 
@@ -99,7 +95,7 @@ func (s *Settings) MergeWith(other Settings) {
 }
 
 func (s *Settings) OverrideWith(other Settings,
-	storage Storage, ipv6Supported bool) (err error) {
+	storage Storage) (err error) {
 	patchedSettings := s.copy()
 	patchedSettings.ControlServer.overrideWith(other.ControlServer)
 	patchedSettings.DNS.overrideWith(other.DNS)
@@ -114,7 +110,7 @@ func (s *Settings) OverrideWith(other Settings,
 	patchedSettings.Version.overrideWith(other.Version)
 	patchedSettings.VPN.OverrideWith(other.VPN)
 	patchedSettings.Pprof.OverrideWith(other.Pprof)
-	err = patchedSettings.Validate(storage, ipv6Supported)
+	err = patchedSettings.Validate(storage)
 	if err != nil {
 		return err
 	}
@@ -161,37 +157,3 @@ func (s Settings) toLinesNode() (node *gotree.Node) {
 
 	return node
 }
-
-func (s Settings) Warnings() (warnings []string) {
-	if *s.VPN.Provider.Name == providers.HideMyAss {
-		warnings = append(warnings, "HideMyAss dropped support for Linux OpenVPN "+
-			" so this will likely not work anymore. See https://github.com/qdm12/gluetun/issues/1498.")
-	}
-
-	if helpers.IsOneOf(*s.VPN.Provider.Name, providers.SlickVPN) &&
-		s.VPN.Type == vpn.OpenVPN {
-		if s.VPN.OpenVPN.Version == openvpn.Openvpn24 {
-			warnings = append(warnings, "OpenVPN 2.4 uses OpenSSL 1.1.1 "+
-				"which allows the usage of weak security in today's standards. "+
-				"This can be ok if good security is enforced by the VPN provider. "+
-				"However, "+*s.VPN.Provider.Name+" uses weak security so you should use "+
-				"OpenVPN 2.5 to enforce good security practices.")
-		} else {
-			warnings = append(warnings, "OpenVPN 2.5 uses OpenSSL 3 "+
-				"which prohibits the usage of weak security in today's standards. "+
-				*s.VPN.Provider.Name+" uses weak security which is out "+
-				"of Gluetun's control so the only workaround is to allow such weaknesses "+
-				`using the OpenVPN option tls-cipher "DEFAULT:@SECLEVEL=0". `+
-				"You might want to reach to your provider so they upgrade their certificates. "+
-				"Once this is done, you will have to let the Gluetun maintainers know "+
-				"by creating an issue, attaching the new certificate and we will update Gluetun.")
-		}
-	}
-
-	if s.VPN.OpenVPN.Version == openvpn.Openvpn24 {
-		warnings = append(warnings, "OpenVPN 2.4 will be removed in release v3.34.0 (around June 2023). "+
-			"Please create an issue if you have a compelling reason to keep it.")
-	}
-
-	return warnings
-}

internal/configuration/settings/settings_test.go

@@ -34,6 +34,7 @@ func Test_Settings_String(t *testing.T) {
 |       ├── User: [not set]
 |       ├── Password: [not set]
 |       ├── Private Internet Access encryption preset: strong
+|       ├── Tunnel IPv6: no
 |       ├── Network interface: tun0
 |       ├── Run OpenVPN as: root
 |       └── Verbosity level: 1
@@ -66,7 +67,6 @@ func Test_Settings_String(t *testing.T) {
 ├── Health settings:
 |   ├── Server listening address: 127.0.0.1:9999
 |   ├── Target address: cloudflare.com:443
-|   ├── Duration to wait after success: 5s
 |   ├── Read header timeout: 100ms
 |   ├── Read timeout: 500ms
 |   └── VPN wait durations:

internal/configuration/settings/shadowsocks.go

@@ -21,7 +21,7 @@ func (s Shadowsocks) validate() (err error) {
 
 func (s *Shadowsocks) copy() (copied Shadowsocks) {
 	return Shadowsocks{
-		Enabled:  helpers.CopyPointer(s.Enabled),
+		Enabled:  helpers.CopyBoolPtr(s.Enabled),
 		Settings: s.Settings.Copy(),
 	}
 }
@@ -29,7 +29,7 @@ func (s *Shadowsocks) copy() (copied Shadowsocks) {
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (s *Shadowsocks) mergeWith(other Shadowsocks) {
-	s.Enabled = helpers.MergeWithPointer(s.Enabled, other.Enabled)
+	s.Enabled = helpers.MergeWithBool(s.Enabled, other.Enabled)
 	s.Settings.MergeWith(other.Settings)
 }
 
@@ -37,12 +37,12 @@ func (s *Shadowsocks) mergeWith(other Shadowsocks) {
 // settings object with any field set in the other
 // settings.
 func (s *Shadowsocks) overrideWith(other Shadowsocks) {
-	s.Enabled = helpers.OverrideWithPointer(s.Enabled, other.Enabled)
+	s.Enabled = helpers.OverrideWithBool(s.Enabled, other.Enabled)
 	s.Settings.OverrideWith(other.Settings)
 }
 
 func (s *Shadowsocks) setDefaults() {
-	s.Enabled = helpers.DefaultPointer(s.Enabled, false)
+	s.Enabled = helpers.DefaultBool(s.Enabled, false)
 	s.Settings.SetDefaults()
 }
 

internal/configuration/settings/system.go

@@ -19,28 +19,28 @@ func (s System) validate() (err error) {
 
 func (s *System) copy() (copied System) {
 	return System{
-		PUID:     helpers.CopyPointer(s.PUID),
-		PGID:     helpers.CopyPointer(s.PGID),
+		PUID:     helpers.CopyUint32Ptr(s.PUID),
+		PGID:     helpers.CopyUint32Ptr(s.PGID),
 		Timezone: s.Timezone,
 	}
 }
 
 func (s *System) mergeWith(other System) {
-	s.PUID = helpers.MergeWithPointer(s.PUID, other.PUID)
-	s.PGID = helpers.MergeWithPointer(s.PGID, other.PGID)
+	s.PUID = helpers.MergeWithUint32(s.PUID, other.PUID)
+	s.PGID = helpers.MergeWithUint32(s.PGID, other.PGID)
 	s.Timezone = helpers.MergeWithString(s.Timezone, other.Timezone)
 }
 
 func (s *System) overrideWith(other System) {
-	s.PUID = helpers.OverrideWithPointer(s.PUID, other.PUID)
-	s.PGID = helpers.OverrideWithPointer(s.PGID, other.PGID)
+	s.PUID = helpers.OverrideWithUint32(s.PUID, other.PUID)
+	s.PGID = helpers.OverrideWithUint32(s.PGID, other.PGID)
 	s.Timezone = helpers.OverrideWithString(s.Timezone, other.Timezone)
 }
 
 func (s *System) setDefaults() {
 	const defaultID = 1000
-	s.PUID = helpers.DefaultPointer(s.PUID, defaultID)
-	s.PGID = helpers.DefaultPointer(s.PGID, defaultID)
+	s.PUID = helpers.DefaultUint32(s.PUID, defaultID)
+	s.PGID = helpers.DefaultUint32(s.PGID, defaultID)
 }
 
 func (s System) String() string {

internal/configuration/settings/unbound.go

@@ -3,12 +3,13 @@ package settings
 import (
 	"errors"
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/dns/pkg/provider"
 	"github.com/qdm12/dns/pkg/unbound"
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gotree"
+	"inet.af/netaddr"
 )
 
 // Unbound is settings for the Unbound program.
@@ -20,7 +21,7 @@ type Unbound struct {
 	VerbosityDetailsLevel *uint8
 	ValidationLogLevel    *uint8
 	Username              string
-	Allowed               []netip.Prefix
+	Allowed               []netaddr.IPPrefix
 }
 
 func (u *Unbound) setDefaults() {
@@ -30,22 +31,22 @@ func (u *Unbound) setDefaults() {
 		}
 	}
 
-	u.Caching = helpers.DefaultPointer(u.Caching, true)
-	u.IPv6 = helpers.DefaultPointer(u.IPv6, false)
+	u.Caching = helpers.DefaultBool(u.Caching, true)
+	u.IPv6 = helpers.DefaultBool(u.IPv6, false)
 
 	const defaultVerbosityLevel = 1
-	u.VerbosityLevel = helpers.DefaultPointer(u.VerbosityLevel, defaultVerbosityLevel)
+	u.VerbosityLevel = helpers.DefaultUint8(u.VerbosityLevel, defaultVerbosityLevel)
 
 	const defaultVerbosityDetailsLevel = 0
-	u.VerbosityDetailsLevel = helpers.DefaultPointer(u.VerbosityDetailsLevel, defaultVerbosityDetailsLevel)
+	u.VerbosityDetailsLevel = helpers.DefaultUint8(u.VerbosityDetailsLevel, defaultVerbosityDetailsLevel)
 
 	const defaultValidationLogLevel = 0
-	u.ValidationLogLevel = helpers.DefaultPointer(u.ValidationLogLevel, defaultValidationLogLevel)
+	u.ValidationLogLevel = helpers.DefaultUint8(u.ValidationLogLevel, defaultValidationLogLevel)
 
 	if u.Allowed == nil {
-		u.Allowed = []netip.Prefix{
-			netip.PrefixFrom(netip.AddrFrom4([4]byte{}), 0),
-			netip.PrefixFrom(netip.AddrFrom16([16]byte{}), 0),
+		u.Allowed = []netaddr.IPPrefix{
+			netaddr.IPPrefixFrom(netaddr.IPv4(0, 0, 0, 0), 0),
+			netaddr.IPPrefixFrom(netaddr.IPv6Raw([16]byte{}), 0),
 		}
 	}
 
@@ -94,37 +95,37 @@ func (u Unbound) validate() (err error) {
 
 func (u Unbound) copy() (copied Unbound) {
 	return Unbound{
-		Providers:             helpers.CopySlice(u.Providers),
-		Caching:               helpers.CopyPointer(u.Caching),
-		IPv6:                  helpers.CopyPointer(u.IPv6),
-		VerbosityLevel:        helpers.CopyPointer(u.VerbosityLevel),
-		VerbosityDetailsLevel: helpers.CopyPointer(u.VerbosityDetailsLevel),
-		ValidationLogLevel:    helpers.CopyPointer(u.ValidationLogLevel),
+		Providers:             helpers.CopyStringSlice(u.Providers),
+		Caching:               helpers.CopyBoolPtr(u.Caching),
+		IPv6:                  helpers.CopyBoolPtr(u.IPv6),
+		VerbosityLevel:        helpers.CopyUint8Ptr(u.VerbosityLevel),
+		VerbosityDetailsLevel: helpers.CopyUint8Ptr(u.VerbosityDetailsLevel),
+		ValidationLogLevel:    helpers.CopyUint8Ptr(u.ValidationLogLevel),
 		Username:              u.Username,
-		Allowed:               helpers.CopySlice(u.Allowed),
+		Allowed:               helpers.CopyIPPrefixSlice(u.Allowed),
 	}
 }
 
 func (u *Unbound) mergeWith(other Unbound) {
-	u.Providers = helpers.MergeSlices(u.Providers, other.Providers)
-	u.Caching = helpers.MergeWithPointer(u.Caching, other.Caching)
-	u.IPv6 = helpers.MergeWithPointer(u.IPv6, other.IPv6)
-	u.VerbosityLevel = helpers.MergeWithPointer(u.VerbosityLevel, other.VerbosityLevel)
-	u.VerbosityDetailsLevel = helpers.MergeWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
-	u.ValidationLogLevel = helpers.MergeWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
+	u.Providers = helpers.MergeStringSlices(u.Providers, other.Providers)
+	u.Caching = helpers.MergeWithBool(u.Caching, other.Caching)
+	u.IPv6 = helpers.MergeWithBool(u.IPv6, other.IPv6)
+	u.VerbosityLevel = helpers.MergeWithUint8(u.VerbosityLevel, other.VerbosityLevel)
+	u.VerbosityDetailsLevel = helpers.MergeWithUint8(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
+	u.ValidationLogLevel = helpers.MergeWithUint8(u.ValidationLogLevel, other.ValidationLogLevel)
 	u.Username = helpers.MergeWithString(u.Username, other.Username)
-	u.Allowed = helpers.MergeSlices(u.Allowed, other.Allowed)
+	u.Allowed = helpers.MergeIPPrefixesSlices(u.Allowed, other.Allowed)
 }
 
 func (u *Unbound) overrideWith(other Unbound) {
-	u.Providers = helpers.OverrideWithSlice(u.Providers, other.Providers)
-	u.Caching = helpers.OverrideWithPointer(u.Caching, other.Caching)
-	u.IPv6 = helpers.OverrideWithPointer(u.IPv6, other.IPv6)
-	u.VerbosityLevel = helpers.OverrideWithPointer(u.VerbosityLevel, other.VerbosityLevel)
-	u.VerbosityDetailsLevel = helpers.OverrideWithPointer(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
-	u.ValidationLogLevel = helpers.OverrideWithPointer(u.ValidationLogLevel, other.ValidationLogLevel)
+	u.Providers = helpers.OverrideWithStringSlice(u.Providers, other.Providers)
+	u.Caching = helpers.OverrideWithBool(u.Caching, other.Caching)
+	u.IPv6 = helpers.OverrideWithBool(u.IPv6, other.IPv6)
+	u.VerbosityLevel = helpers.OverrideWithUint8(u.VerbosityLevel, other.VerbosityLevel)
+	u.VerbosityDetailsLevel = helpers.OverrideWithUint8(u.VerbosityDetailsLevel, other.VerbosityDetailsLevel)
+	u.ValidationLogLevel = helpers.OverrideWithUint8(u.ValidationLogLevel, other.ValidationLogLevel)
 	u.Username = helpers.OverrideWithString(u.Username, other.Username)
-	u.Allowed = helpers.OverrideWithSlice(u.Allowed, other.Allowed)
+	u.Allowed = helpers.OverrideWithIPPrefixesSlice(u.Allowed, other.Allowed)
 }
 
 func (u Unbound) ToUnboundFormat() (settings unbound.Settings, err error) {
@@ -148,30 +149,20 @@ func (u Unbound) ToUnboundFormat() (settings unbound.Settings, err error) {
 		VerbosityDetailsLevel: *u.VerbosityDetailsLevel,
 		ValidationLogLevel:    *u.ValidationLogLevel,
 		AccessControl: unbound.AccessControlSettings{
-			Allowed: netipPrefixesToNetaddrIPPrefixes(u.Allowed),
+			Allowed: u.Allowed,
 		},
 		Username: u.Username,
 	}, nil
 }
 
-var (
-	ErrConvertingNetip = errors.New("converting net.IP to netip.Addr failed")
-)
-
-func (u Unbound) GetFirstPlaintextIPv4() (ipv4 netip.Addr, err error) {
+func (u Unbound) GetFirstPlaintextIPv4() (ipv4 net.IP, err error) {
 	s := u.Providers[0]
 	provider, err := provider.Parse(s)
 	if err != nil {
-		return ipv4, err
+		return nil, err
 	}
 
-	ip := provider.DNS().IPv4[0]
-	ipv4, ok := netip.AddrFromSlice(ip)
-	if !ok {
-		return ipv4, fmt.Errorf("%w: for ip %s (%#v)",
-			ErrConvertingNetip, ip, ip)
-	}
-	return ipv4.Unmap(), nil
+	return provider.DNS().IPv4[0], nil
 }
 
 func (u Unbound) String() string {

internal/configuration/settings/unbound_test.go

@@ -2,11 +2,11 @@ package settings
 
 import (
 	"encoding/json"
-	"net/netip"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"inet.af/netaddr"
 )
 
 func Test_Unbound_JSON(t *testing.T) {
@@ -20,9 +20,9 @@ func Test_Unbound_JSON(t *testing.T) {
 		VerbosityDetailsLevel: nil,
 		ValidationLogLevel:    uint8Ptr(0),
 		Username:              "user",
-		Allowed: []netip.Prefix{
-			netip.PrefixFrom(netip.AddrFrom4([4]byte{}), 0),
-			netip.PrefixFrom(netip.AddrFrom16([16]byte{}), 0),
+		Allowed: []netaddr.IPPrefix{
+			netaddr.IPPrefixFrom(netaddr.IPv4(0, 0, 0, 0), 0),
+			netaddr.IPPrefixFrom(netaddr.IPv6Raw([16]byte{}), 0),
 		},
 	}
 

internal/configuration/settings/updater.go

@@ -63,34 +63,34 @@ func (u Updater) Validate() (err error) {
 
 func (u *Updater) copy() (copied Updater) {
 	return Updater{
-		Period:     helpers.CopyPointer(u.Period),
+		Period:     helpers.CopyDurationPtr(u.Period),
 		DNSAddress: u.DNSAddress,
 		MinRatio:   u.MinRatio,
-		Providers:  helpers.CopySlice(u.Providers),
+		Providers:  helpers.CopyStringSlice(u.Providers),
 	}
 }
 
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (u *Updater) mergeWith(other Updater) {
-	u.Period = helpers.MergeWithPointer(u.Period, other.Period)
+	u.Period = helpers.MergeWithDurationPtr(u.Period, other.Period)
 	u.DNSAddress = helpers.MergeWithString(u.DNSAddress, other.DNSAddress)
-	u.MinRatio = helpers.MergeWithNumber(u.MinRatio, other.MinRatio)
-	u.Providers = helpers.MergeSlices(u.Providers, other.Providers)
+	u.MinRatio = helpers.MergeWithFloat64(u.MinRatio, other.MinRatio)
+	u.Providers = helpers.MergeStringSlices(u.Providers, other.Providers)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (u *Updater) overrideWith(other Updater) {
-	u.Period = helpers.OverrideWithPointer(u.Period, other.Period)
+	u.Period = helpers.OverrideWithDurationPtr(u.Period, other.Period)
 	u.DNSAddress = helpers.OverrideWithString(u.DNSAddress, other.DNSAddress)
-	u.MinRatio = helpers.OverrideWithNumber(u.MinRatio, other.MinRatio)
-	u.Providers = helpers.OverrideWithSlice(u.Providers, other.Providers)
+	u.MinRatio = helpers.OverrideWithFloat64(u.MinRatio, other.MinRatio)
+	u.Providers = helpers.OverrideWithStringSlice(u.Providers, other.Providers)
 }
 
 func (u *Updater) SetDefaults(vpnProvider string) {
-	u.Period = helpers.DefaultPointer(u.Period, 0)
+	u.Period = helpers.DefaultDurationPtr(u.Period, 0)
 	u.DNSAddress = helpers.DefaultString(u.DNSAddress, "1.1.1.1:53")
 
 	if u.MinRatio == 0 {

internal/configuration/settings/version.go

@@ -19,25 +19,25 @@ func (v Version) validate() (err error) {
 
 func (v *Version) copy() (copied Version) {
 	return Version{
-		Enabled: helpers.CopyPointer(v.Enabled),
+		Enabled: helpers.CopyBoolPtr(v.Enabled),
 	}
 }
 
 // mergeWith merges the other settings into any
 // unset field of the receiver settings object.
 func (v *Version) mergeWith(other Version) {
-	v.Enabled = helpers.MergeWithPointer(v.Enabled, other.Enabled)
+	v.Enabled = helpers.MergeWithBool(v.Enabled, other.Enabled)
 }
 
 // overrideWith overrides fields of the receiver
 // settings object with any field set in the other
 // settings.
 func (v *Version) overrideWith(other Version) {
-	v.Enabled = helpers.OverrideWithPointer(v.Enabled, other.Enabled)
+	v.Enabled = helpers.OverrideWithBool(v.Enabled, other.Enabled)
 }
 
 func (v *Version) setDefaults() {
-	v.Enabled = helpers.DefaultPointer(v.Enabled, true)
+	v.Enabled = helpers.DefaultBool(v.Enabled, true)
 }
 
 func (v Version) String() string {

internal/configuration/settings/vpn.go

@@ -20,7 +20,7 @@ type VPN struct {
 }
 
 // TODO v4 remove pointer for receiver (because of Surfshark).
-func (v *VPN) Validate(storage Storage, ipv6Supported bool) (err error) {
+func (v *VPN) Validate(storage Storage) (err error) {
 	// Validate Type
 	validVPNTypes := []string{vpn.OpenVPN, vpn.Wireguard}
 	if !helpers.IsOneOf(v.Type, validVPNTypes...) {
@@ -39,7 +39,7 @@ func (v *VPN) Validate(storage Storage, ipv6Supported bool) (err error) {
 			return fmt.Errorf("OpenVPN settings: %w", err)
 		}
 	} else {
-		err := v.Wireguard.validate(*v.Provider.Name, ipv6Supported)
+		err := v.Wireguard.validate(*v.Provider.Name)
 		if err != nil {
 			return fmt.Errorf("Wireguard settings: %w", err)
 		}

internal/configuration/settings/wireguard.go

@@ -2,7 +2,7 @@ package settings
 
 import (
 	"fmt"
-	"net/netip"
+	"net"
 	"regexp"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
@@ -22,28 +22,22 @@ type Wireguard struct {
 	// It cannot be nil in the internal state.
 	PreSharedKey *string
 	// Addresses are the Wireguard interface addresses.
-	Addresses []netip.Prefix
+	Addresses []net.IPNet
 	// Interface is the name of the Wireguard interface
 	// to create. It cannot be the empty string in the
 	// internal state.
 	Interface string
-	// Implementation is the Wireguard implementation to use.
-	// It can be "auto", "userspace" or "kernelspace".
-	// It defaults to "auto" and cannot be the empty string
-	// in the internal state.
-	Implementation string
 }
 
 var regexpInterfaceName = regexp.MustCompile(`^[a-zA-Z0-9_]+$`)
 
 // Validate validates Wireguard settings.
 // It should only be ran if the VPN type chosen is Wireguard.
-func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error) {
+func (w Wireguard) validate(vpnProvider string) (err error) {
 	if !helpers.IsOneOf(vpnProvider,
 		providers.Custom,
 		providers.Ivpn,
 		providers.Mullvad,
-		providers.Surfshark,
 		providers.Windscribe,
 	) {
 		// do not validate for VPN provider not supporting Wireguard
@@ -52,19 +46,13 @@ func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error)
 
 	// Validate PrivateKey
 	if *w.PrivateKey == "" {
-		return fmt.Errorf("%w", ErrWireguardPrivateKeyNotSet)
+		return ErrWireguardPrivateKeyNotSet
 	}
 	_, err = wgtypes.ParseKey(*w.PrivateKey)
 	if err != nil {
 		return fmt.Errorf("private key is not valid: %w", err)
 	}
 
-	if vpnProvider == providers.Airvpn {
-		if *w.PreSharedKey == "" {
-			return fmt.Errorf("%w", ErrWireguardPreSharedKeyNotSet)
-		}
-	}
-
 	// Validate PreSharedKey
 	if *w.PreSharedKey != "" { // Note: this is optional
 		_, err = wgtypes.ParseKey(*w.PreSharedKey)
@@ -75,18 +63,13 @@ func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error)
 
 	// Validate Addresses
 	if len(w.Addresses) == 0 {
-		return fmt.Errorf("%w", ErrWireguardInterfaceAddressNotSet)
+		return ErrWireguardInterfaceAddressNotSet
 	}
 	for i, ipNet := range w.Addresses {
-		if !ipNet.IsValid() {
+		if ipNet.IP == nil || ipNet.Mask == nil {
 			return fmt.Errorf("%w: for address at index %d: %s",
 				ErrWireguardInterfaceAddressNotSet, i, ipNet.String())
 		}
-
-		if !ipv6Supported && ipNet.Addr().Is6() {
-			return fmt.Errorf("%w: address %s",
-				ErrWireguardInterfaceAddressIPv6, ipNet)
-		}
 	}
 
 	// Validate interface
@@ -95,46 +78,36 @@ func (w Wireguard) validate(vpnProvider string, ipv6Supported bool) (err error)
 			ErrWireguardInterfaceNotValid, w.Interface, regexpInterfaceName)
 	}
 
-	validImplementations := []string{"auto", "userspace", "kernelspace"}
-	if !helpers.IsOneOf(w.Implementation, validImplementations...) {
-		return fmt.Errorf("%w: %s must be one of %s", ErrWireguardImplementationNotValid,
-			w.Implementation, helpers.ChoicesOrString(validImplementations))
-	}
-
 	return nil
 }
 
 func (w *Wireguard) copy() (copied Wireguard) {
 	return Wireguard{
-		PrivateKey:     helpers.CopyPointer(w.PrivateKey),
-		PreSharedKey:   helpers.CopyPointer(w.PreSharedKey),
-		Addresses:      helpers.CopySlice(w.Addresses),
-		Interface:      w.Interface,
-		Implementation: w.Implementation,
+		PrivateKey:   helpers.CopyStringPtr(w.PrivateKey),
+		PreSharedKey: helpers.CopyStringPtr(w.PreSharedKey),
+		Addresses:    helpers.CopyIPNetSlice(w.Addresses),
+		Interface:    w.Interface,
 	}
 }
 
 func (w *Wireguard) mergeWith(other Wireguard) {
-	w.PrivateKey = helpers.MergeWithPointer(w.PrivateKey, other.PrivateKey)
-	w.PreSharedKey = helpers.MergeWithPointer(w.PreSharedKey, other.PreSharedKey)
-	w.Addresses = helpers.MergeSlices(w.Addresses, other.Addresses)
+	w.PrivateKey = helpers.MergeWithStringPtr(w.PrivateKey, other.PrivateKey)
+	w.PreSharedKey = helpers.MergeWithStringPtr(w.PreSharedKey, other.PreSharedKey)
+	w.Addresses = helpers.MergeIPNetsSlices(w.Addresses, other.Addresses)
 	w.Interface = helpers.MergeWithString(w.Interface, other.Interface)
-	w.Implementation = helpers.MergeWithString(w.Implementation, other.Implementation)
 }
 
 func (w *Wireguard) overrideWith(other Wireguard) {
-	w.PrivateKey = helpers.OverrideWithPointer(w.PrivateKey, other.PrivateKey)
-	w.PreSharedKey = helpers.OverrideWithPointer(w.PreSharedKey, other.PreSharedKey)
-	w.Addresses = helpers.OverrideWithSlice(w.Addresses, other.Addresses)
+	w.PrivateKey = helpers.OverrideWithStringPtr(w.PrivateKey, other.PrivateKey)
+	w.PreSharedKey = helpers.OverrideWithStringPtr(w.PreSharedKey, other.PreSharedKey)
+	w.Addresses = helpers.OverrideWithIPNetsSlice(w.Addresses, other.Addresses)
 	w.Interface = helpers.OverrideWithString(w.Interface, other.Interface)
-	w.Implementation = helpers.OverrideWithString(w.Implementation, other.Implementation)
 }
 
 func (w *Wireguard) setDefaults() {
-	w.PrivateKey = helpers.DefaultPointer(w.PrivateKey, "")
-	w.PreSharedKey = helpers.DefaultPointer(w.PreSharedKey, "")
+	w.PrivateKey = helpers.DefaultStringPtr(w.PrivateKey, "")
+	w.PreSharedKey = helpers.DefaultStringPtr(w.PreSharedKey, "")
 	w.Interface = helpers.DefaultString(w.Interface, "wg0")
-	w.Implementation = helpers.DefaultString(w.Implementation, "auto")
 }
 
 func (w Wireguard) String() string {
@@ -161,9 +134,5 @@ func (w Wireguard) toLinesNode() (node *gotree.Node) {
 
 	node.Appendf("Network interface: %s", w.Interface)
 
-	if w.Implementation != "auto" {
-		node.Appendf("Implementation: %s", w.Implementation)
-	}
-
 	return node
 }

internal/configuration/settings/wireguardselection.go

@@ -2,7 +2,7 @@ package settings
 
 import (
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings/helpers"
 	"github.com/qdm12/gluetun/internal/constants/providers"
@@ -15,11 +15,11 @@ type WireguardSelection struct {
 	// It is only used with VPN providers generating Wireguard
 	// configurations specific to each server and user.
 	// To indicate it should not be used, it should be set
-	// to netaddr.IPv4Unspecified(). It can never be the zero value
+	// to the empty net.IP{} slice. It can never be nil
 	// in the internal state.
-	EndpointIP netip.Addr
+	EndpointIP net.IP
 	// EndpointPort is a the server port to use for the VPN server.
-	// It is optional for VPN providers IVPN, Mullvad, Surfshark
+	// It is optional for VPN providers IVPN, Mullvad
 	// and Windscribe, and compulsory for the others.
 	// When optional, it can be set to 0 to indicate not use
 	// a custom endpoint port. It cannot be nil in the internal
@@ -36,12 +36,10 @@ type WireguardSelection struct {
 func (w WireguardSelection) validate(vpnProvider string) (err error) {
 	// Validate EndpointIP
 	switch vpnProvider {
-	case providers.Airvpn, providers.Ivpn, providers.Mullvad,
-		providers.Surfshark, providers.Windscribe:
-		// endpoint IP addresses are baked in
+	case providers.Ivpn, providers.Mullvad, providers.Windscribe: // endpoint IP addresses are baked in
 	case providers.Custom:
-		if !w.EndpointIP.IsValid() || w.EndpointIP.IsUnspecified() {
-			return fmt.Errorf("%w", ErrWireguardEndpointIPNotSet)
+		if len(w.EndpointIP) == 0 {
+			return ErrWireguardEndpointIPNotSet
 		}
 	default: // Providers not supporting Wireguard
 	}
@@ -51,14 +49,9 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 	// EndpointPort is required
 	case providers.Custom:
 		if *w.EndpointPort == 0 {
-			return fmt.Errorf("%w", ErrWireguardEndpointPortNotSet)
+			return ErrWireguardEndpointPortNotSet
 		}
-	// EndpointPort cannot be set
-	case providers.Surfshark:
-		if *w.EndpointPort != 0 {
-			return fmt.Errorf("%w", ErrWireguardEndpointPortSet)
-		}
-	case providers.Airvpn, providers.Ivpn, providers.Mullvad, providers.Windscribe:
+	case providers.Ivpn, providers.Mullvad, providers.Windscribe:
 		// EndpointPort is optional and can be 0
 		if *w.EndpointPort == 0 {
 			break // no custom endpoint port set
@@ -68,8 +61,6 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 		}
 		var allowed []uint16
 		switch vpnProvider {
-		case providers.Airvpn:
-			allowed = []uint16{1637, 47107}
 		case providers.Ivpn:
 			allowed = []uint16{2049, 2050, 53, 30587, 41893, 48574, 58237}
 		case providers.Windscribe:
@@ -87,12 +78,10 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 
 	// Validate PublicKey
 	switch vpnProvider {
-	case providers.Ivpn, providers.Mullvad,
-		providers.Surfshark, providers.Windscribe:
-		// public keys are baked in
+	case providers.Ivpn, providers.Mullvad, providers.Windscribe: // public keys are baked in
 	case providers.Custom:
 		if w.PublicKey == "" {
-			return fmt.Errorf("%w", ErrWireguardPublicKeyNotSet)
+			return ErrWireguardPublicKeyNotSet
 		}
 	default: // Providers not supporting Wireguard
 	}
@@ -109,27 +98,27 @@ func (w WireguardSelection) validate(vpnProvider string) (err error) {
 
 func (w *WireguardSelection) copy() (copied WireguardSelection) {
 	return WireguardSelection{
-		EndpointIP:   w.EndpointIP,
-		EndpointPort: helpers.CopyPointer(w.EndpointPort),
+		EndpointIP:   helpers.CopyIP(w.EndpointIP),
+		EndpointPort: helpers.CopyUint16Ptr(w.EndpointPort),
 		PublicKey:    w.PublicKey,
 	}
 }
 
 func (w *WireguardSelection) mergeWith(other WireguardSelection) {
 	w.EndpointIP = helpers.MergeWithIP(w.EndpointIP, other.EndpointIP)
-	w.EndpointPort = helpers.MergeWithPointer(w.EndpointPort, other.EndpointPort)
+	w.EndpointPort = helpers.MergeWithUint16(w.EndpointPort, other.EndpointPort)
 	w.PublicKey = helpers.MergeWithString(w.PublicKey, other.PublicKey)
 }
 
 func (w *WireguardSelection) overrideWith(other WireguardSelection) {
 	w.EndpointIP = helpers.OverrideWithIP(w.EndpointIP, other.EndpointIP)
-	w.EndpointPort = helpers.OverrideWithPointer(w.EndpointPort, other.EndpointPort)
+	w.EndpointPort = helpers.OverrideWithUint16(w.EndpointPort, other.EndpointPort)
 	w.PublicKey = helpers.OverrideWithString(w.PublicKey, other.PublicKey)
 }
 
 func (w *WireguardSelection) setDefaults() {
-	w.EndpointIP = helpers.DefaultIP(w.EndpointIP, netip.IPv4Unspecified())
-	w.EndpointPort = helpers.DefaultPointer(w.EndpointPort, 0)
+	w.EndpointIP = helpers.DefaultIP(w.EndpointIP, net.IP{})
+	w.EndpointPort = helpers.DefaultUint16(w.EndpointPort, 0)
 }
 
 func (w WireguardSelection) String() string {
@@ -139,7 +128,7 @@ func (w WireguardSelection) String() string {
 func (w WireguardSelection) toLinesNode() (node *gotree.Node) {
 	node = gotree.New("Wireguard selection settings:")
 
-	if !w.EndpointIP.IsUnspecified() {
+	if len(w.EndpointIP) > 0 {
 		node.Appendf("Endpoint IP address: %s", w.EndpointIP)
 	}
 

internal/configuration/sources/env/dns.go

@@ -2,13 +2,13 @@ package env
 
 import (
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readDNS() (dns settings.DNS, err error) {
-	dns.ServerAddress, err = s.readDNSServerAddress()
+func (r *Reader) readDNS() (dns settings.DNS, err error) {
+	dns.ServerAddress, err = r.readDNSServerAddress()
 	if err != nil {
 		return dns, err
 	}
@@ -18,7 +18,7 @@ func (s *Source) readDNS() (dns settings.DNS, err error) {
 		return dns, fmt.Errorf("environment variable DNS_KEEP_NAMESERVER: %w", err)
 	}
 
-	dns.DoT, err = s.readDoT()
+	dns.DoT, err = r.readDoT()
 	if err != nil {
 		return dns, fmt.Errorf("DoT settings: %w", err)
 	}
@@ -26,22 +26,22 @@ func (s *Source) readDNS() (dns settings.DNS, err error) {
 	return dns, nil
 }
 
-func (s *Source) readDNSServerAddress() (address netip.Addr, err error) {
-	key, value := s.getEnvWithRetro("DNS_ADDRESS", "DNS_PLAINTEXT_ADDRESS")
-	if value == "" {
-		return address, nil
+func (r *Reader) readDNSServerAddress() (address net.IP, err error) {
+	key, s := r.getEnvWithRetro("DNS_ADDRESS", "DNS_PLAINTEXT_ADDRESS")
+	if s == "" {
+		return nil, nil
 	}
 
-	address, err = netip.ParseAddr(value)
-	if err != nil {
-		return address, fmt.Errorf("environment variable %s: %w", key, err)
+	address = net.ParseIP(s)
+	if address == nil {
+		return nil, fmt.Errorf("environment variable %s: %w: %s", key, ErrIPAddressParse, s)
 	}
 
 	// TODO remove in v4
-	if address.Unmap().Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
-		s.warner.Warn(key + " is set to " + value +
+	if !address.Equal(net.IPv4(127, 0, 0, 1)) { //nolint:gomnd
+		r.warner.Warn(key + " is set to " + s +
 			" so the DNS over TLS (DoT) server will not be used." +
-			" The default value changed to 127.0.0.1 so it uses the internal DoT serves." +
+			" The default value changed to 127.0.0.1 so it uses the internal DoT server." +
 			" If the DoT server fails to start, the IPv4 address of the first plaintext DNS server" +
 			" corresponding to the first DoT provider chosen is used.")
 	}

internal/configuration/sources/env/dnsblacklist.go

@@ -3,19 +3,19 @@ package env
 import (
 	"errors"
 	"fmt"
-	"net/netip"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/govalid/binary"
+	"inet.af/netaddr"
 )
 
-func (s *Source) readDNSBlacklist() (blacklist settings.DNSBlacklist, err error) {
+func (r *Reader) readDNSBlacklist() (blacklist settings.DNSBlacklist, err error) {
 	blacklist.BlockMalicious, err = envToBoolPtr("BLOCK_MALICIOUS")
 	if err != nil {
 		return blacklist, fmt.Errorf("environment variable BLOCK_MALICIOUS: %w", err)
 	}
 
-	blacklist.BlockSurveillance, err = s.readBlockSurveillance()
+	blacklist.BlockSurveillance, err = r.readBlockSurveillance()
 	if err != nil {
 		return blacklist, err
 	}
@@ -36,8 +36,8 @@ func (s *Source) readDNSBlacklist() (blacklist settings.DNSBlacklist, err error)
 	return blacklist, nil
 }
 
-func (s *Source) readBlockSurveillance() (blocked *bool, err error) {
-	key, value := s.getEnvWithRetro("BLOCK_SURVEILLANCE", "BLOCK_NSA")
+func (r *Reader) readBlockSurveillance() (blocked *bool, err error) {
+	key, value := r.getEnvWithRetro("BLOCK_SURVEILLANCE", "BLOCK_NSA")
 	if value == "" {
 		return nil, nil //nolint:nilnil
 	}
@@ -55,24 +55,24 @@ var (
 	ErrPrivateAddressNotValid = errors.New("private address is not a valid IP or CIDR range")
 )
 
-func readDoTPrivateAddresses() (ips []netip.Addr,
-	ipPrefixes []netip.Prefix, err error) {
+func readDoTPrivateAddresses() (ips []netaddr.IP,
+	ipPrefixes []netaddr.IPPrefix, err error) {
 	privateAddresses := envToCSV("DOT_PRIVATE_ADDRESS")
 	if len(privateAddresses) == 0 {
 		return nil, nil, nil
 	}
 
-	ips = make([]netip.Addr, 0, len(privateAddresses))
-	ipPrefixes = make([]netip.Prefix, 0, len(privateAddresses))
+	ips = make([]netaddr.IP, 0, len(privateAddresses))
+	ipPrefixes = make([]netaddr.IPPrefix, 0, len(privateAddresses))
 
 	for _, privateAddress := range privateAddresses {
-		ip, err := netip.ParseAddr(privateAddress)
+		ip, err := netaddr.ParseIP(privateAddress)
 		if err == nil {
 			ips = append(ips, ip)
 			continue
 		}
 
-		ipPrefix, err := netip.ParsePrefix(privateAddress)
+		ipPrefix, err := netaddr.ParseIPPrefix(privateAddress)
 		if err == nil {
 			ipPrefixes = append(ipPrefixes, ipPrefix)
 			continue

internal/configuration/sources/env/dot.go

@@ -6,7 +6,7 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readDoT() (dot settings.DoT, err error) {
+func (r *Reader) readDoT() (dot settings.DoT, err error) {
 	dot.Enabled, err = envToBoolPtr("DOT")
 	if err != nil {
 		return dot, fmt.Errorf("environment variable DOT: %w", err)
@@ -22,7 +22,7 @@ func (s *Source) readDoT() (dot settings.DoT, err error) {
 		return dot, err
 	}
 
-	dot.Blacklist, err = s.readDNSBlacklist()
+	dot.Blacklist, err = r.readDNSBlacklist()
 	if err != nil {
 		return dot, err
 	}

internal/configuration/sources/env/firewall.go

@@ -3,13 +3,13 @@ package env
 import (
 	"errors"
 	"fmt"
-	"net/netip"
+	"net"
 	"strconv"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readFirewall() (firewall settings.Firewall, err error) {
+func (r *Reader) readFirewall() (firewall settings.Firewall, err error) {
 	vpnInputPortStrings := envToCSV("FIREWALL_VPN_INPUT_PORTS")
 	firewall.VPNInputPorts, err = stringsToPorts(vpnInputPortStrings)
 	if err != nil {
@@ -22,9 +22,9 @@ func (s *Source) readFirewall() (firewall settings.Firewall, err error) {
 		return firewall, fmt.Errorf("environment variable FIREWALL_INPUT_PORTS: %w", err)
 	}
 
-	outboundSubnetsKey, _ := s.getEnvWithRetro("FIREWALL_OUTBOUND_SUBNETS", "EXTRA_SUBNETS")
+	outboundSubnetsKey, _ := r.getEnvWithRetro("FIREWALL_OUTBOUND_SUBNETS", "EXTRA_SUBNETS")
 	outboundSubnetStrings := envToCSV(outboundSubnetsKey)
-	firewall.OutboundSubnets, err = stringsToNetipPrefixes(outboundSubnetStrings)
+	firewall.OutboundSubnets, err = stringsToIPNets(outboundSubnetStrings)
 	if err != nil {
 		return firewall, fmt.Errorf("environment variable %s: %w", outboundSubnetsKey, err)
 	}
@@ -65,16 +65,18 @@ func stringsToPorts(ss []string) (ports []uint16, err error) {
 	return ports, nil
 }
 
-func stringsToNetipPrefixes(ss []string) (ipPrefixes []netip.Prefix, err error) {
+func stringsToIPNets(ss []string) (ipNets []net.IPNet, err error) {
 	if len(ss) == 0 {
 		return nil, nil
 	}
-	ipPrefixes = make([]netip.Prefix, len(ss))
+	ipNets = make([]net.IPNet, len(ss))
 	for i, s := range ss {
-		ipPrefixes[i], err = netip.ParsePrefix(s)
+		ip, ipNet, err := net.ParseCIDR(s)
 		if err != nil {
-			return nil, fmt.Errorf("parsing IP network %q: %w", s, err)
+			return nil, fmt.Errorf("cannot parse IP network %q: %w", s, err)
 		}
+		ipNet.IP = ip
+		ipNets[i] = *ipNet
 	}
-	return ipPrefixes, nil
+	return ipNets, nil
 }

internal/configuration/sources/env/health.go

@@ -7,25 +7,18 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) ReadHealth() (health settings.Health, err error) {
+func (r *Reader) ReadHealth() (health settings.Health, err error) {
 	health.ServerAddress = getCleanedEnv("HEALTH_SERVER_ADDRESS")
-	_, health.TargetAddress = s.getEnvWithRetro("HEALTH_TARGET_ADDRESS", "HEALTH_ADDRESS_TO_PING")
+	_, health.TargetAddress = r.getEnvWithRetro("HEALTH_TARGET_ADDRESS", "HEALTH_ADDRESS_TO_PING")
 
-	successWaitPtr, err := envToDurationPtr("HEALTH_SUCCESS_WAIT_DURATION")
-	if err != nil {
-		return health, fmt.Errorf("environment variable HEALTH_SUCCESS_WAIT_DURATION: %w", err)
-	} else if successWaitPtr != nil {
-		health.SuccessWait = *successWaitPtr
-	}
-
-	health.VPN.Initial, err = s.readDurationWithRetro(
+	health.VPN.Initial, err = r.readDurationWithRetro(
 		"HEALTH_VPN_DURATION_INITIAL",
 		"HEALTH_OPENVPN_DURATION_INITIAL")
 	if err != nil {
 		return health, err
 	}
 
-	health.VPN.Addition, err = s.readDurationWithRetro(
+	health.VPN.Addition, err = r.readDurationWithRetro(
 		"HEALTH_VPN_DURATION_ADDITION",
 		"HEALTH_OPENVPN_DURATION_ADDITION")
 	if err != nil {
@@ -35,14 +28,14 @@ func (s *Source) ReadHealth() (health settings.Health, err error) {
 	return health, nil
 }
 
-func (s *Source) readDurationWithRetro(envKey, retroEnvKey string) (d *time.Duration, err error) {
-	envKey, value := s.getEnvWithRetro(envKey, retroEnvKey)
-	if value == "" {
+func (r *Reader) readDurationWithRetro(envKey, retroEnvKey string) (d *time.Duration, err error) {
+	envKey, s := r.getEnvWithRetro(envKey, retroEnvKey)
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}
 
 	d = new(time.Duration)
-	*d, err = time.ParseDuration(value)
+	*d, err = time.ParseDuration(s)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", envKey, err)
 	}

internal/configuration/sources/env/helpers.go

@@ -29,6 +29,14 @@ func envToCSV(envKey string) (values []string) {
 	return lowerAndSplit(csv)
 }
 
+func envToInt(envKey string) (n int, err error) {
+	s := getCleanedEnv(envKey)
+	if s == "" {
+		return 0, nil
+	}
+	return strconv.Atoi(s)
+}
+
 func envToFloat64(envKey string) (f float64, err error) {
 	s := getCleanedEnv(envKey)
 	if s == "" {
@@ -129,7 +137,7 @@ func unsetEnvKeys(envKeys []string, err error) (newErr error) {
 	for _, envKey := range envKeys {
 		unsetErr := os.Unsetenv(envKey)
 		if unsetErr != nil && newErr == nil {
-			newErr = fmt.Errorf("unsetting environment variable %s: %w", envKey, unsetErr)
+			newErr = fmt.Errorf("cannot unset environment variable %s: %w", envKey, unsetErr)
 		}
 	}
 	return newErr

internal/configuration/sources/env/httproxy.go

@@ -7,12 +7,12 @@ import (
 	"github.com/qdm12/govalid/binary"
 )
 
-func (s *Source) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
-	httpProxy.User = s.readHTTProxyUser()
-	httpProxy.Password = s.readHTTProxyPassword()
-	httpProxy.ListeningAddress = s.readHTTProxyListeningAddress()
+func (r *Reader) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
+	httpProxy.User = r.readHTTProxyUser()
+	httpProxy.Password = r.readHTTProxyPassword()
+	httpProxy.ListeningAddress = r.readHTTProxyListeningAddress()
 
-	httpProxy.Enabled, err = s.readHTTProxyEnabled()
+	httpProxy.Enabled, err = r.readHTTProxyEnabled()
 	if err != nil {
 		return httpProxy, err
 	}
@@ -22,7 +22,7 @@ func (s *Source) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
 		return httpProxy, fmt.Errorf("environment variable HTTPPROXY_STEALTH: %w", err)
 	}
 
-	httpProxy.Log, err = s.readHTTProxyLog()
+	httpProxy.Log, err = r.readHTTProxyLog()
 	if err != nil {
 		return httpProxy, err
 	}
@@ -30,38 +30,38 @@ func (s *Source) readHTTPProxy() (httpProxy settings.HTTPProxy, err error) {
 	return httpProxy, nil
 }
 
-func (s *Source) readHTTProxyUser() (user *string) {
-	_, value := s.getEnvWithRetro("HTTPPROXY_USER", "PROXY_USER", "TINYPROXY_USER")
-	if value != "" {
-		return &value
+func (r *Reader) readHTTProxyUser() (user *string) {
+	_, s := r.getEnvWithRetro("HTTPPROXY_USER", "PROXY_USER", "TINYPROXY_USER")
+	if s != "" {
+		return &s
 	}
 	return nil
 }
 
-func (s *Source) readHTTProxyPassword() (user *string) {
-	_, value := s.getEnvWithRetro("HTTPPROXY_PASSWORD", "PROXY_PASSWORD", "TINYPROXY_PASSWORD")
-	if value != "" {
-		return &value
+func (r *Reader) readHTTProxyPassword() (user *string) {
+	_, s := r.getEnvWithRetro("HTTPPROXY_PASSWORD", "PROXY_PASSWORD", "TINYPROXY_PASSWORD")
+	if s != "" {
+		return &s
 	}
 	return nil
 }
 
-func (s *Source) readHTTProxyListeningAddress() (listeningAddress string) {
-	key, value := s.getEnvWithRetro("HTTPPROXY_LISTENING_ADDRESS", "PROXY_PORT", "TINYPROXY_PORT", "HTTPPROXY_PORT")
+func (r *Reader) readHTTProxyListeningAddress() (listeningAddress string) {
+	key, value := r.getEnvWithRetro("HTTPPROXY_LISTENING_ADDRESS", "PROXY_PORT", "TINYPROXY_PORT", "HTTPPROXY_PORT")
 	if key == "HTTPPROXY_LISTENING_ADDRESS" {
 		return value
 	}
 	return ":" + value
 }
 
-func (s *Source) readHTTProxyEnabled() (enabled *bool, err error) {
-	key, value := s.getEnvWithRetro("HTTPPROXY", "PROXY", "TINYPROXY")
-	if value == "" {
+func (r *Reader) readHTTProxyEnabled() (enabled *bool, err error) {
+	key, s := r.getEnvWithRetro("HTTPPROXY", "PROXY", "TINYPROXY")
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}
 
 	enabled = new(bool)
-	*enabled, err = binary.Validate(value)
+	*enabled, err = binary.Validate(s)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", key, err)
 	}
@@ -69,9 +69,9 @@ func (s *Source) readHTTProxyEnabled() (enabled *bool, err error) {
 	return enabled, nil
 }
 
-func (s *Source) readHTTProxyLog() (enabled *bool, err error) {
-	key, value := s.getEnvWithRetro("HTTPPROXY_LOG", "PROXY_LOG_LEVEL", "TINYPROXY_LOG")
-	if value == "" {
+func (r *Reader) readHTTProxyLog() (enabled *bool, err error) {
+	key, s := r.getEnvWithRetro("HTTPPROXY_LOG", "PROXY_LOG_LEVEL", "TINYPROXY_LOG")
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}
 
@@ -82,7 +82,7 @@ func (s *Source) readHTTProxyLog() (enabled *bool, err error) {
 	}
 
 	enabled = new(bool)
-	*enabled, err = binary.Validate(value, binaryOptions...)
+	*enabled, err = binary.Validate(s, binaryOptions...)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", key, err)
 	}

internal/configuration/sources/env/openvpn.go

@@ -8,7 +8,7 @@ import (
 	"github.com/qdm12/govalid/binary"
 )
 
-func (s *Source) readOpenVPN() (
+func (r *Reader) readOpenVPN() (
 	openVPN settings.OpenVPN, err error) {
 	defer func() {
 		err = unsetEnvKeys([]string{"OPENVPN_KEY", "OPENVPN_CERT",
@@ -16,14 +16,14 @@ func (s *Source) readOpenVPN() (
 	}()
 
 	openVPN.Version = getCleanedEnv("OPENVPN_VERSION")
-	openVPN.User = s.readOpenVPNUser()
-	openVPN.Password = s.readOpenVPNPassword()
+	openVPN.User = r.readOpenVPNUser()
+	openVPN.Password = r.readOpenVPNPassword()
 	confFile := getCleanedEnv("OPENVPN_CUSTOM_CONFIG")
 	if confFile != "" {
 		openVPN.ConfFile = &confFile
 	}
 
-	ciphersKey, _ := s.getEnvWithRetro("OPENVPN_CIPHERS", "OPENVPN_CIPHER")
+	ciphersKey, _ := r.getEnvWithRetro("OPENVPN_CIPHERS", "OPENVPN_CIPHER")
 	openVPN.Ciphers = envToCSV(ciphersKey)
 
 	auth := getCleanedEnv("OPENVPN_AUTH")
@@ -35,18 +35,23 @@ func (s *Source) readOpenVPN() (
 	openVPN.Key = envToStringPtr("OPENVPN_KEY")
 	openVPN.EncryptedKey = envToStringPtr("OPENVPN_ENCRYPTED_KEY")
 
-	openVPN.KeyPassphrase = s.readOpenVPNKeyPassphrase()
+	openVPN.KeyPassphrase = r.readOpenVPNKeyPassphrase()
 
-	openVPN.PIAEncPreset = s.readPIAEncryptionPreset()
+	openVPN.PIAEncPreset = r.readPIAEncryptionPreset()
+
+	openVPN.IPv6, err = envToBoolPtr("OPENVPN_IPV6")
+	if err != nil {
+		return openVPN, fmt.Errorf("environment variable OPENVPN_IPV6: %w", err)
+	}
 
 	openVPN.MSSFix, err = envToUint16Ptr("OPENVPN_MSSFIX")
 	if err != nil {
 		return openVPN, fmt.Errorf("environment variable OPENVPN_MSSFIX: %w", err)
 	}
 
-	_, openVPN.Interface = s.getEnvWithRetro("VPN_INTERFACE", "OPENVPN_INTERFACE")
+	_, openVPN.Interface = r.getEnvWithRetro("VPN_INTERFACE", "OPENVPN_INTERFACE")
 
-	openVPN.ProcessUser, err = s.readOpenVPNProcessUser()
+	openVPN.ProcessUser, err = r.readOpenVPNProcessUser()
 	if err != nil {
 		return openVPN, err
 	}
@@ -64,9 +69,9 @@ func (s *Source) readOpenVPN() (
 	return openVPN, nil
 }
 
-func (s *Source) readOpenVPNUser() (user *string) {
+func (r *Reader) readOpenVPNUser() (user *string) {
 	user = new(string)
-	_, *user = s.getEnvWithRetro("OPENVPN_USER", "USER")
+	_, *user = r.getEnvWithRetro("OPENVPN_USER", "USER")
 	if *user == "" {
 		return nil
 	}
@@ -76,9 +81,9 @@ func (s *Source) readOpenVPNUser() (user *string) {
 	return user
 }
 
-func (s *Source) readOpenVPNPassword() (password *string) {
+func (r *Reader) readOpenVPNPassword() (password *string) {
 	password = new(string)
-	_, *password = s.getEnvWithRetro("OPENVPN_PASSWORD", "PASSWORD")
+	_, *password = r.getEnvWithRetro("OPENVPN_PASSWORD", "PASSWORD")
 	if *password == "" {
 		return nil
 	}
@@ -86,7 +91,7 @@ func (s *Source) readOpenVPNPassword() (password *string) {
 	return password
 }
 
-func (s *Source) readOpenVPNKeyPassphrase() (passphrase *string) {
+func (r *Reader) readOpenVPNKeyPassphrase() (passphrase *string) {
 	passphrase = new(string)
 	*passphrase = getCleanedEnv("OPENVPN_KEY_PASSPHRASE")
 	if *passphrase == "" {
@@ -95,8 +100,8 @@ func (s *Source) readOpenVPNKeyPassphrase() (passphrase *string) {
 	return passphrase
 }
 
-func (s *Source) readPIAEncryptionPreset() (presetPtr *string) {
-	_, preset := s.getEnvWithRetro(
+func (r *Reader) readPIAEncryptionPreset() (presetPtr *string) {
+	_, preset := r.getEnvWithRetro(
 		"PRIVATE_INTERNET_ACCESS_OPENVPN_ENCRYPTION_PRESET",
 		"PIA_ENCRYPTION", "ENCRYPTION")
 	if preset != "" {
@@ -105,8 +110,8 @@ func (s *Source) readPIAEncryptionPreset() (presetPtr *string) {
 	return nil
 }
 
-func (s *Source) readOpenVPNProcessUser() (processUser string, err error) {
-	key, value := s.getEnvWithRetro("OPENVPN_PROCESS_USER", "OPENVPN_ROOT")
+func (r *Reader) readOpenVPNProcessUser() (processUser string, err error) {
+	key, value := r.getEnvWithRetro("OPENVPN_PROCESS_USER", "OPENVPN_ROOT")
 	if key == "OPENVPN_PROCESS_USER" {
 		return value, nil
 	}

internal/configuration/sources/env/openvpnselection.go

@@ -10,32 +10,32 @@ import (
 	"github.com/qdm12/govalid/port"
 )
 
-func (s *Source) readOpenVPNSelection() (
+func (r *Reader) readOpenVPNSelection() (
 	selection settings.OpenVPNSelection, err error) {
 	confFile := getCleanedEnv("OPENVPN_CUSTOM_CONFIG")
 	if confFile != "" {
 		selection.ConfFile = &confFile
 	}
 
-	selection.TCP, err = s.readOpenVPNProtocol()
+	selection.TCP, err = r.readOpenVPNProtocol()
 	if err != nil {
 		return selection, err
 	}
 
-	selection.CustomPort, err = s.readOpenVPNCustomPort()
+	selection.CustomPort, err = r.readOpenVPNCustomPort()
 	if err != nil {
 		return selection, err
 	}
 
-	selection.PIAEncPreset = s.readPIAEncryptionPreset()
+	selection.PIAEncPreset = r.readPIAEncryptionPreset()
 
 	return selection, nil
 }
 
 var ErrOpenVPNProtocolNotValid = errors.New("OpenVPN protocol is not valid")
 
-func (s *Source) readOpenVPNProtocol() (tcp *bool, err error) {
-	envKey, protocol := s.getEnvWithRetro("OPENVPN_PROTOCOL", "PROTOCOL")
+func (r *Reader) readOpenVPNProtocol() (tcp *bool, err error) {
+	envKey, protocol := r.getEnvWithRetro("OPENVPN_PROTOCOL", "PROTOCOL")
 
 	switch strings.ToLower(protocol) {
 	case "":
@@ -50,14 +50,14 @@ func (s *Source) readOpenVPNProtocol() (tcp *bool, err error) {
 	}
 }
 
-func (s *Source) readOpenVPNCustomPort() (customPort *uint16, err error) {
-	key, value := s.getEnvWithRetro("VPN_ENDPOINT_PORT", "PORT", "OPENVPN_PORT")
-	if value == "" {
+func (r *Reader) readOpenVPNCustomPort() (customPort *uint16, err error) {
+	key, s := r.getEnvWithRetro("VPN_ENDPOINT_PORT", "PORT", "OPENVPN_PORT")
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}
 
 	customPort = new(uint16)
-	*customPort, err = port.Validate(value)
+	*customPort, err = port.Validate(s)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", key, err)
 	}

internal/configuration/sources/env/portforward.go

@@ -6,10 +6,9 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readPortForward() (
+func (r *Reader) readPortForward() (
 	portForwarding settings.PortForwarding, err error) {
-	key, _ := s.getEnvWithRetro(
-		"VPN_PORT_FORWARDING",
+	key, _ := r.getEnvWithRetro(
 		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING",
 		"PORT_FORWARDING")
 	portForwarding.Enabled, err = envToBoolPtr(key)
@@ -17,8 +16,7 @@ func (s *Source) readPortForward() (
 		return portForwarding, fmt.Errorf("environment variable %s: %w", key, err)
 	}
 
-	_, value := s.getEnvWithRetro(
-		"VPN_PORT_FORWARDING_STATUS_FILE",
+	_, value := r.getEnvWithRetro(
 		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE",
 		"PORT_FORWARDING_STATUS_FILE")
 	if value != "" {

internal/configuration/sources/env/pprof.go

@@ -12,12 +12,12 @@ func readPprof() (settings pprof.Settings, err error) {
 		return settings, fmt.Errorf("environment variable PPROF_ENABLED: %w", err)
 	}
 
-	settings.BlockProfileRate, err = envToIntPtr("PPROF_BLOCK_PROFILE_RATE")
+	settings.BlockProfileRate, err = envToInt("PPROF_BLOCK_PROFILE_RATE")
 	if err != nil {
 		return settings, fmt.Errorf("environment variable PPROF_BLOCK_PROFILE_RATE: %w", err)
 	}
 
-	settings.MutexProfileRate, err = envToIntPtr("PPROF_MUTEX_PROFILE_RATE")
+	settings.MutexProfileRate, err = envToInt("PPROF_MUTEX_PROFILE_RATE")
 	if err != nil {
 		return settings, fmt.Errorf("environment variable PPROF_MUTEX_PROFILE_RATE: %w", err)
 	}

internal/configuration/sources/env/provider.go

@@ -9,19 +9,19 @@ import (
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 )
 
-func (s *Source) readProvider(vpnType string) (provider settings.Provider, err error) {
-	provider.Name = s.readVPNServiceProvider(vpnType)
+func (r *Reader) readProvider(vpnType string) (provider settings.Provider, err error) {
+	provider.Name = r.readVPNServiceProvider(vpnType)
 	var providerName string
 	if provider.Name != nil {
 		providerName = *provider.Name
 	}
 
-	provider.ServerSelection, err = s.readServerSelection(providerName, vpnType)
+	provider.ServerSelection, err = r.readServerSelection(providerName, vpnType)
 	if err != nil {
 		return provider, fmt.Errorf("server selection: %w", err)
 	}
 
-	provider.PortForwarding, err = s.readPortForward()
+	provider.PortForwarding, err = r.readPortForward()
 	if err != nil {
 		return provider, fmt.Errorf("port forwarding: %w", err)
 	}
@@ -29,20 +29,17 @@ func (s *Source) readProvider(vpnType string) (provider settings.Provider, err e
 	return provider, nil
 }
 
-func (s *Source) readVPNServiceProvider(vpnType string) (vpnProviderPtr *string) {
-	_, value := s.getEnvWithRetro("VPN_SERVICE_PROVIDER", "VPNSP")
-	if value == "" {
-		if vpnType != vpn.Wireguard && getCleanedEnv("OPENVPN_CUSTOM_CONFIG") != "" {
-			// retro compatibility
-			return stringPtr(providers.Custom)
-		}
+func (r *Reader) readVPNServiceProvider(vpnType string) (vpnProviderPtr *string) {
+	_, s := r.getEnvWithRetro("VPN_SERVICE_PROVIDER", "VPNSP")
+	s = strings.ToLower(s)
+	switch {
+	case vpnType != vpn.Wireguard &&
+		getCleanedEnv("OPENVPN_CUSTOM_CONFIG") != "": // retro compatibility
+		return stringPtr(providers.Custom)
+	case s == "":
 		return nil
-	}
-
-	value = strings.ToLower(value)
-	if value == "pia" { // retro compatibility
+	case s == "pia": // retro compatibility
 		return stringPtr(providers.PrivateInternetAccess)
 	}
-
-	return stringPtr(value)
+	return stringPtr(s)
 }

internal/configuration/sources/env/publicip.go

@@ -7,13 +7,13 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readPublicIP() (publicIP settings.PublicIP, err error) {
+func (r *Reader) readPublicIP() (publicIP settings.PublicIP, err error) {
 	publicIP.Period, err = readPublicIPPeriod()
 	if err != nil {
 		return publicIP, err
 	}
 
-	publicIP.IPFilepath = s.readPublicIPFilepath()
+	publicIP.IPFilepath = r.readPublicIPFilepath()
 
 	return publicIP, nil
 }
@@ -33,10 +33,10 @@ func readPublicIPPeriod() (period *time.Duration, err error) {
 	return period, nil
 }
 
-func (s *Source) readPublicIPFilepath() (filepath *string) {
-	_, value := s.getEnvWithRetro("PUBLICIP_FILE", "IP_STATUS_FILE")
-	if value != "" {
-		return &value
+func (r *Reader) readPublicIPFilepath() (filepath *string) {
+	_, s := r.getEnvWithRetro("PUBLICIP_FILE", "IP_STATUS_FILE")
+	if s != "" {
+		return &s
 	}
 	return nil
 }

internal/configuration/sources/env/reader.go

@@ -2,9 +2,12 @@ package env
 
 import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 )
 
-type Source struct {
+var _ sources.Source = (*Reader)(nil)
+
+type Reader struct {
 	warner Warner
 }
 
@@ -12,36 +15,36 @@ type Warner interface {
 	Warn(s string)
 }
 
-func New(warner Warner) *Source {
-	return &Source{
+func New(warner Warner) *Reader {
+	return &Reader{
 		warner: warner,
 	}
 }
 
-func (s *Source) String() string { return "environment variables" }
+func (r *Reader) String() string { return "environment variables" }
 
-func (s *Source) Read() (settings settings.Settings, err error) {
-	settings.VPN, err = s.readVPN()
+func (r *Reader) Read() (settings settings.Settings, err error) {
+	settings.VPN, err = r.readVPN()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.Firewall, err = s.readFirewall()
+	settings.Firewall, err = r.readFirewall()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.System, err = s.readSystem()
+	settings.System, err = r.readSystem()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.Health, err = s.ReadHealth()
+	settings.Health, err = r.ReadHealth()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.HTTPProxy, err = s.readHTTPProxy()
+	settings.HTTPProxy, err = r.readHTTPProxy()
 	if err != nil {
 		return settings, err
 	}
@@ -51,7 +54,7 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}
 
-	settings.PublicIP, err = s.readPublicIP()
+	settings.PublicIP, err = r.readPublicIP()
 	if err != nil {
 		return settings, err
 	}
@@ -66,17 +69,17 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 		return settings, err
 	}
 
-	settings.Shadowsocks, err = s.readShadowsocks()
+	settings.Shadowsocks, err = r.readShadowsocks()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.DNS, err = s.readDNS()
+	settings.DNS, err = r.readDNS()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.ControlServer, err = s.readControlServer()
+	settings.ControlServer, err = r.readControlServer()
 	if err != nil {
 		return settings, err
 	}
@@ -89,8 +92,8 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 	return settings, nil
 }
 
-func (s *Source) onRetroActive(oldKey, newKey string) {
-	s.warner.Warn(
+func (r *Reader) onRetroActive(oldKey, newKey string) {
+	r.warner.Warn(
 		"You are using the old environment variable " + oldKey +
 			", please consider changing it to " + newKey)
 }
@@ -101,14 +104,14 @@ func (s *Source) onRetroActive(oldKey, newKey string) {
 // and end on returning the value corresponding to the currentKey.
 // Note retroKeys should be in order from oldest to most
 // recent retro-compatibility key.
-func (s *Source) getEnvWithRetro(currentKey string,
+func (r *Reader) getEnvWithRetro(currentKey string,
 	retroKeys ...string) (key, value string) {
 	// We check retro-compatibility keys first since
 	// the current key might be set in the Dockerfile.
 	for _, key = range retroKeys {
 		value = getCleanedEnv(key)
 		if value != "" {
-			s.onRetroActive(key, currentKey)
+			r.onRetroActive(key, currentKey)
 			return key, value
 		}
 	}

internal/configuration/sources/env/server.go

@@ -7,13 +7,13 @@ import (
 	"github.com/qdm12/govalid/binary"
 )
 
-func (s *Source) readControlServer() (controlServer settings.ControlServer, err error) {
+func (r *Reader) readControlServer() (controlServer settings.ControlServer, err error) {
 	controlServer.Log, err = readControlServerLog()
 	if err != nil {
 		return controlServer, err
 	}
 
-	controlServer.Address = s.readControlServerAddress()
+	controlServer.Address = r.readControlServerAddress()
 
 	return controlServer, nil
 }
@@ -32,17 +32,17 @@ func readControlServerLog() (enabled *bool, err error) {
 	return &log, nil
 }
 
-func (s *Source) readControlServerAddress() (address *string) {
-	key, value := s.getEnvWithRetro("HTTP_CONTROL_SERVER_ADDRESS", "HTTP_CONTROL_SERVER_PORT")
-	if value == "" {
+func (r *Reader) readControlServerAddress() (address *string) {
+	key, s := r.getEnvWithRetro("HTTP_CONTROL_SERVER_ADDRESS", "HTTP_CONTROL_SERVER_PORT")
+	if s == "" {
 		return nil
 	}
 
 	if key == "HTTP_CONTROL_SERVER_ADDRESS" {
-		return &value
+		return &s
 	}
 
 	address = new(string)
-	*address = ":" + value
+	*address = ":" + s
 	return address
 }

internal/configuration/sources/env/serverselection.go

@@ -3,7 +3,7 @@ package env
 import (
 	"errors"
 	"fmt"
-	"net/netip"
+	"net"
 	"strconv"
 	"strings"
 
@@ -15,45 +15,44 @@ var (
 	ErrServerNumberNotValid = errors.New("server number is not valid")
 )
 
-func (s *Source) readServerSelection(vpnProvider, vpnType string) (
+func (r *Reader) readServerSelection(vpnProvider, vpnType string) (
 	ss settings.ServerSelection, err error) {
 	ss.VPN = vpnType
 
-	ss.TargetIP, err = s.readOpenVPNTargetIP()
+	ss.TargetIP, err = r.readOpenVPNTargetIP()
 	if err != nil {
 		return ss, err
 	}
 
-	countriesKey, _ := s.getEnvWithRetro("SERVER_COUNTRIES", "COUNTRY")
+	countriesKey, _ := r.getEnvWithRetro("SERVER_COUNTRIES", "COUNTRY")
 	ss.Countries = envToCSV(countriesKey)
 	if vpnProvider == providers.Cyberghost && len(ss.Countries) == 0 {
 		// Retro-compatibility for Cyberghost using the REGION variable
 		ss.Countries = envToCSV("REGION")
 		if len(ss.Countries) > 0 {
-			s.onRetroActive("REGION", "SERVER_COUNTRIES")
+			r.onRetroActive("REGION", "SERVER_COUNTRIES")
 		}
 	}
 
-	regionsKey, _ := s.getEnvWithRetro("SERVER_REGIONS", "REGION")
+	regionsKey, _ := r.getEnvWithRetro("SERVER_REGIONS", "REGION")
 	ss.Regions = envToCSV(regionsKey)
 
-	citiesKey, _ := s.getEnvWithRetro("SERVER_CITIES", "CITY")
+	citiesKey, _ := r.getEnvWithRetro("SERVER_CITIES", "CITY")
 	ss.Cities = envToCSV(citiesKey)
 
 	ss.ISPs = envToCSV("ISP")
 
-	hostnamesKey, _ := s.getEnvWithRetro("SERVER_HOSTNAMES", "SERVER_HOSTNAME")
+	hostnamesKey, _ := r.getEnvWithRetro("SERVER_HOSTNAMES", "SERVER_HOSTNAME")
 	ss.Hostnames = envToCSV(hostnamesKey)
 
-	serverNamesKey, _ := s.getEnvWithRetro("SERVER_NAMES", "SERVER_NAME")
+	serverNamesKey, _ := r.getEnvWithRetro("SERVER_NAMES", "SERVER_NAME")
 	ss.Names = envToCSV(serverNamesKey)
 
 	if csv := getCleanedEnv("SERVER_NUMBER"); csv != "" {
 		numbersStrings := strings.Split(csv, ",")
 		numbers := make([]uint16, len(numbersStrings))
 		for i, numberString := range numbersStrings {
-			const base, bitSize = 10, 16
-			number, err := strconv.ParseInt(numberString, base, bitSize)
+			number, err := strconv.Atoi(numberString)
 			if err != nil {
 				return ss, fmt.Errorf("%w: %s",
 					ErrServerNumberNotValid, numberString)
@@ -67,7 +66,7 @@ func (s *Source) readServerSelection(vpnProvider, vpnType string) (
 	}
 
 	// Mullvad only
-	ss.OwnedOnly, err = s.readOwnedOnly()
+	ss.OwnedOnly, err = r.readOwnedOnly()
 	if err != nil {
 		return ss, err
 	}
@@ -96,12 +95,12 @@ func (s *Source) readServerSelection(vpnProvider, vpnType string) (
 		return ss, fmt.Errorf("environment variable STREAM_ONLY: %w", err)
 	}
 
-	ss.OpenVPN, err = s.readOpenVPNSelection()
+	ss.OpenVPN, err = r.readOpenVPNSelection()
 	if err != nil {
 		return ss, err
 	}
 
-	ss.Wireguard, err = s.readWireguardSelection()
+	ss.Wireguard, err = r.readWireguardSelection()
 	if err != nil {
 		return ss, err
 	}
@@ -113,22 +112,23 @@ var (
 	ErrInvalidIP = errors.New("invalid IP address")
 )
 
-func (s *Source) readOpenVPNTargetIP() (ip netip.Addr, err error) {
-	envKey, value := s.getEnvWithRetro("VPN_ENDPOINT_IP", "OPENVPN_TARGET_IP")
-	if value == "" {
-		return ip, nil
+func (r *Reader) readOpenVPNTargetIP() (ip net.IP, err error) {
+	envKey, s := r.getEnvWithRetro("VPN_ENDPOINT_IP", "OPENVPN_TARGET_IP")
+	if s == "" {
+		return nil, nil
 	}
 
-	ip, err = netip.ParseAddr(value)
-	if err != nil {
-		return ip, fmt.Errorf("environment variable %s: %w", envKey, err)
+	ip = net.ParseIP(s)
+	if ip == nil {
+		return nil, fmt.Errorf("environment variable %s: %w: %s",
+			envKey, ErrInvalidIP, s)
 	}
 
 	return ip, nil
 }
 
-func (s *Source) readOwnedOnly() (ownedOnly *bool, err error) {
-	envKey, _ := s.getEnvWithRetro("OWNED_ONLY", "OWNED")
+func (r *Reader) readOwnedOnly() (ownedOnly *bool, err error) {
+	envKey, _ := r.getEnvWithRetro("OWNED_ONLY", "OWNED")
 	ownedOnly, err = envToBoolPtr(envKey)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", envKey, err)

internal/configuration/sources/env/shadowsocks.go

@@ -7,25 +7,25 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readShadowsocks() (shadowsocks settings.Shadowsocks, err error) {
+func (r *Reader) readShadowsocks() (shadowsocks settings.Shadowsocks, err error) {
 	shadowsocks.Enabled, err = envToBoolPtr("SHADOWSOCKS")
 	if err != nil {
 		return shadowsocks, fmt.Errorf("environment variable SHADOWSOCKS: %w", err)
 	}
 
-	shadowsocks.Address = s.readShadowsocksAddress()
+	shadowsocks.Address = r.readShadowsocksAddress()
 	shadowsocks.LogAddresses, err = envToBoolPtr("SHADOWSOCKS_LOG")
 	if err != nil {
 		return shadowsocks, fmt.Errorf("environment variable SHADOWSOCKS_LOG: %w", err)
 	}
-	shadowsocks.CipherName = s.readShadowsocksCipher()
+	shadowsocks.CipherName = r.readShadowsocksCipher()
 	shadowsocks.Password = envToStringPtr("SHADOWSOCKS_PASSWORD")
 
 	return shadowsocks, nil
 }
 
-func (s *Source) readShadowsocksAddress() (address string) {
-	key, value := s.getEnvWithRetro("SHADOWSOCKS_LISTENING_ADDRESS", "SHADOWSOCKS_PORT")
+func (r *Reader) readShadowsocksAddress() (address string) {
+	key, value := r.getEnvWithRetro("SHADOWSOCKS_LISTENING_ADDRESS", "SHADOWSOCKS_PORT")
 	if value == "" {
 		return ""
 	}
@@ -38,7 +38,7 @@ func (s *Source) readShadowsocksAddress() (address string) {
 	return ":" + value
 }
 
-func (s *Source) readShadowsocksCipher() (cipher string) {
-	_, cipher = s.getEnvWithRetro("SHADOWSOCKS_CIPHER", "SHADOWSOCKS_METHOD")
+func (r *Reader) readShadowsocksCipher() (cipher string) {
+	_, cipher = r.getEnvWithRetro("SHADOWSOCKS_CIPHER", "SHADOWSOCKS_METHOD")
 	return strings.ToLower(cipher)
 }

internal/configuration/sources/env/system.go

@@ -14,13 +14,13 @@ var (
 	ErrSystemTimezoneNotValid = errors.New("timezone is not valid")
 )
 
-func (s *Source) readSystem() (system settings.System, err error) {
-	system.PUID, err = s.readID("PUID", "UID")
+func (r *Reader) readSystem() (system settings.System, err error) {
+	system.PUID, err = r.readID("PUID", "UID")
 	if err != nil {
 		return system, err
 	}
 
-	system.PGID, err = s.readID("PGID", "GID")
+	system.PGID, err = r.readID("PGID", "GID")
 	if err != nil {
 		return system, err
 	}
@@ -32,9 +32,9 @@ func (s *Source) readSystem() (system settings.System, err error) {
 
 var ErrSystemIDNotValid = errors.New("system ID is not valid")
 
-func (s *Source) readID(key, retroKey string) (
+func (r *Reader) readID(key, retroKey string) (
 	id *uint32, err error) {
-	idEnvKey, idString := s.getEnvWithRetro(key, retroKey)
+	idEnvKey, idString := r.getEnvWithRetro(key, retroKey)
 	if idString == "" {
 		return nil, nil //nolint:nilnil
 	}

internal/configuration/sources/env/system_test.go

@@ -74,8 +74,8 @@ func Test_Reader_readID(t *testing.T) {
 			setTestEnv(t, key, testCase.keyValue)
 			setTestEnv(t, retroKey, testCase.retroValue)
 
-			source := &Source{}
-			id, err := source.readID(key, retroKey)
+			reader := &Reader{}
+			id, err := reader.readID(key, retroKey)
 
 			assert.ErrorIs(t, err, testCase.errWrapped)
 			if err != nil {

internal/configuration/sources/env/vpn.go

@@ -7,20 +7,20 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readVPN() (vpn settings.VPN, err error) {
+func (r *Reader) readVPN() (vpn settings.VPN, err error) {
 	vpn.Type = strings.ToLower(getCleanedEnv("VPN_TYPE"))
 
-	vpn.Provider, err = s.readProvider(vpn.Type)
+	vpn.Provider, err = r.readProvider(vpn.Type)
 	if err != nil {
 		return vpn, fmt.Errorf("VPN provider: %w", err)
 	}
 
-	vpn.OpenVPN, err = s.readOpenVPN()
+	vpn.OpenVPN, err = r.readOpenVPN()
 	if err != nil {
 		return vpn, fmt.Errorf("OpenVPN: %w", err)
 	}
 
-	vpn.Wireguard, err = s.readWireguard()
+	vpn.Wireguard, err = r.readWireguard()
 	if err != nil {
 		return vpn, fmt.Errorf("wireguard: %w", err)
 	}

internal/configuration/sources/env/wireguard.go

@@ -2,42 +2,41 @@ package env
 
 import (
 	"fmt"
-	"net/netip"
-	"os"
+	"net"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readWireguard() (wireguard settings.Wireguard, err error) {
+func (r *Reader) readWireguard() (wireguard settings.Wireguard, err error) {
 	defer func() {
 		err = unsetEnvKeys([]string{"WIREGUARD_PRIVATE_KEY", "WIREGUARD_PRESHARED_KEY"}, err)
 	}()
 	wireguard.PrivateKey = envToStringPtr("WIREGUARD_PRIVATE_KEY")
 	wireguard.PreSharedKey = envToStringPtr("WIREGUARD_PRESHARED_KEY")
-	_, wireguard.Interface = s.getEnvWithRetro("VPN_INTERFACE", "WIREGUARD_INTERFACE")
-	wireguard.Implementation = os.Getenv("WIREGUARD_IMPLEMENTATION")
-	wireguard.Addresses, err = s.readWireguardAddresses()
+	_, wireguard.Interface = r.getEnvWithRetro("VPN_INTERFACE", "WIREGUARD_INTERFACE")
+	wireguard.Addresses, err = r.readWireguardAddresses()
 	if err != nil {
 		return wireguard, err // already wrapped
 	}
 	return wireguard, nil
 }
 
-func (s *Source) readWireguardAddresses() (addresses []netip.Prefix, err error) {
-	key, addressesCSV := s.getEnvWithRetro("WIREGUARD_ADDRESSES", "WIREGUARD_ADDRESS")
+func (r *Reader) readWireguardAddresses() (addresses []net.IPNet, err error) {
+	key, addressesCSV := r.getEnvWithRetro("WIREGUARD_ADDRESSES", "WIREGUARD_ADDRESS")
 	if addressesCSV == "" {
 		return nil, nil
 	}
 
 	addressStrings := strings.Split(addressesCSV, ",")
-	addresses = make([]netip.Prefix, len(addressStrings))
+	addresses = make([]net.IPNet, len(addressStrings))
 	for i, addressString := range addressStrings {
-		addressString = strings.TrimSpace(addressString)
-		addresses[i], err = netip.ParsePrefix(addressString)
+		ip, ipNet, err := net.ParseCIDR(addressString)
 		if err != nil {
 			return nil, fmt.Errorf("environment variable %s: %w", key, err)
 		}
+		ipNet.IP = ip
+		addresses[i] = *ipNet
 	}
 
 	return addresses, nil

internal/configuration/sources/env/wireguardselection.go

@@ -1,21 +1,22 @@
 package env
 
 import (
+	"errors"
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/govalid/port"
 )
 
-func (s *Source) readWireguardSelection() (
+func (r *Reader) readWireguardSelection() (
 	selection settings.WireguardSelection, err error) {
-	selection.EndpointIP, err = s.readWireguardEndpointIP()
+	selection.EndpointIP, err = r.readWireguardEndpointIP()
 	if err != nil {
 		return selection, err
 	}
 
-	selection.EndpointPort, err = s.readWireguardCustomPort()
+	selection.EndpointPort, err = r.readWireguardCustomPort()
 	if err != nil {
 		return selection, err
 	}
@@ -25,28 +26,31 @@ func (s *Source) readWireguardSelection() (
 	return selection, nil
 }
 
-func (s *Source) readWireguardEndpointIP() (endpointIP netip.Addr, err error) {
-	key, value := s.getEnvWithRetro("VPN_ENDPOINT_IP", "WIREGUARD_ENDPOINT_IP")
-	if value == "" {
-		return endpointIP, nil
+var ErrIPAddressParse = errors.New("cannot parse IP address")
+
+func (r *Reader) readWireguardEndpointIP() (endpointIP net.IP, err error) {
+	key, s := r.getEnvWithRetro("VPN_ENDPOINT_IP", "WIREGUARD_ENDPOINT_IP")
+	if s == "" {
+		return nil, nil
 	}
 
-	endpointIP, err = netip.ParseAddr(value)
-	if err != nil {
-		return endpointIP, fmt.Errorf("environment variable %s: %w", key, err)
+	endpointIP = net.ParseIP(s)
+	if endpointIP == nil {
+		return nil, fmt.Errorf("environment variable %s: %w: %s",
+			key, ErrIPAddressParse, s)
 	}
 
 	return endpointIP, nil
 }
 
-func (s *Source) readWireguardCustomPort() (customPort *uint16, err error) {
-	key, value := s.getEnvWithRetro("VPN_ENDPOINT_PORT", "WIREGUARD_ENDPOINT_PORT")
-	if value == "" {
+func (r *Reader) readWireguardCustomPort() (customPort *uint16, err error) {
+	key, s := r.getEnvWithRetro("VPN_ENDPOINT_PORT", "WIREGUARD_ENDPOINT_PORT")
+	if s == "" {
 		return nil, nil //nolint:nilnil
 	}
 
 	customPort = new(uint16)
-	*customPort, err = port.Validate(value)
+	*customPort, err = port.Validate(s)
 	if err != nil {
 		return nil, fmt.Errorf("environment variable %s: %w", key, err)
 	}

internal/configuration/sources/files/health.go

@@ -2,4 +2,4 @@ package files
 
 import "github.com/qdm12/gluetun/internal/configuration/settings"
 
-func (s *Source) ReadHealth() (settings settings.Health, err error) { return settings, nil }
+func (r *Reader) ReadHealth() (settings settings.Health, err error) { return settings, nil }

internal/configuration/sources/files/openvpn.go

@@ -14,7 +14,7 @@ const (
 	openVPNEncryptedKey          = "/gluetun/openvpn_encrypted_key"
 )
 
-func (s *Source) readOpenVPN() (settings settings.OpenVPN, err error) {
+func (r *Reader) readOpenVPN() (settings settings.OpenVPN, err error) {
 	settings.Key, err = readPEMFile(OpenVPNClientKeyPath)
 	if err != nil {
 		return settings, fmt.Errorf("client key: %w", err)

internal/configuration/sources/files/reader.go

@@ -2,23 +2,26 @@ package files
 
 import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 )
 
-type Source struct{}
+var _ sources.Source = (*Reader)(nil)
 
-func New() *Source {
-	return &Source{}
+type Reader struct{}
+
+func New() *Reader {
+	return &Reader{}
 }
 
-func (s *Source) String() string { return "files" }
+func (r *Reader) String() string { return "files" }
 
-func (s *Source) Read() (settings settings.Settings, err error) {
-	settings.VPN, err = s.readVPN()
+func (r *Reader) Read() (settings settings.Settings, err error) {
+	settings.VPN, err = r.readVPN()
 	if err != nil {
 		return settings, err
 	}
 
-	settings.System, err = s.readSystem()
+	settings.System, err = r.readSystem()
 	if err != nil {
 		return settings, err
 	}

internal/configuration/sources/files/system.go

@@ -4,7 +4,7 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readSystem() (system settings.System, err error) {
+func (r *Reader) readSystem() (system settings.System, err error) {
 	// TODO timezone from /etc/localtime
 	return system, nil
 }

internal/configuration/sources/files/vpn.go

@@ -6,8 +6,8 @@ import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
 )
 
-func (s *Source) readVPN() (vpn settings.VPN, err error) {
-	vpn.OpenVPN, err = s.readOpenVPN()
+func (r *Reader) readVPN() (vpn settings.VPN, err error) {
+	vpn.OpenVPN, err = r.readOpenVPN()
 	if err != nil {
 		return vpn, fmt.Errorf("OpenVPN: %w", err)
 	}

internal/configuration/sources/mux/reader.go

@@ -1,32 +1,29 @@
-package merge
+package mux
 
 import (
 	"fmt"
 	"strings"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 )
 
-type ConfigSource interface {
-	Read() (settings settings.Settings, err error)
-	ReadHealth() (settings settings.Health, err error)
-	String() string
+var _ sources.Source = (*Reader)(nil)
+
+type Reader struct {
+	sources []sources.Source
 }
 
-type Source struct {
-	sources []ConfigSource
-}
-
-func New(sources ...ConfigSource) *Source {
-	return &Source{
+func New(sources ...sources.Source) *Reader {
+	return &Reader{
 		sources: sources,
 	}
 }
 
-func (s *Source) String() string {
-	sources := make([]string, len(s.sources))
-	for i := range s.sources {
-		sources[i] = s.sources[i].String()
+func (r *Reader) String() string {
+	sources := make([]string, len(r.sources))
+	for i := range r.sources {
+		sources[i] = r.sources[i].String()
 	}
 	return strings.Join(sources, ", ")
 }
@@ -34,8 +31,8 @@ func (s *Source) String() string {
 // Read reads the settings for each source, merging unset fields
 // with field set by the next source.
 // It then set defaults to remaining unset fields.
-func (s *Source) Read() (settings settings.Settings, err error) {
-	for _, source := range s.sources {
+func (r *Reader) Read() (settings settings.Settings, err error) {
+	for _, source := range r.sources {
 		settingsFromSource, err := source.Read()
 		if err != nil {
 			return settings, fmt.Errorf("reading from %s: %w", source, err)
@@ -50,8 +47,8 @@ func (s *Source) Read() (settings settings.Settings, err error) {
 // with field set by the next source.
 // It then set defaults to remaining unset fields, and validate
 // all the fields.
-func (s *Source) ReadHealth() (settings settings.Health, err error) {
-	for _, source := range s.sources {
+func (r *Reader) ReadHealth() (settings settings.Health, err error) {
+	for _, source := range r.sources {
 		settingsFromSource, err := source.ReadHealth()
 		if err != nil {
 			return settings, fmt.Errorf("reading from %s: %w", source, err)

internal/configuration/sources/secrets/health.go

@@ -2,4 +2,4 @@ package secrets
 
 import "github.com/qdm12/gluetun/internal/configuration/settings"
 
-func (s *Source) ReadHealth() (settings settings.Health, err error) { return settings, nil }
+func (r *Reader) ReadHealth() (settings settings.Health, err error) { return settings, nil }

internal/configuration/sources/secrets/httpproxy.go

@@ -12,7 +12,7 @@ func readHTTPProxy() (settings settings.HTTPProxy, err error) {
 		"/run/secrets/httpproxy_user",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading HTTP proxy user secret file: %w", err)
+		return settings, fmt.Errorf("cannot read HTTP proxy user secret file: %w", err)
 	}
 
 	settings.Password, err = readSecretFileAsStringPtr(
@@ -20,7 +20,7 @@ func readHTTPProxy() (settings settings.HTTPProxy, err error) {
 		"/run/secrets/httpproxy_password",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading OpenVPN password secret file: %w", err)
+		return settings, fmt.Errorf("cannot read OpenVPN password secret file: %w", err)
 	}
 
 	return settings, nil

internal/configuration/sources/secrets/openvpn.go

@@ -13,7 +13,7 @@ func readOpenVPN() (
 		"/run/secrets/openvpn_user",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading user file: %w", err)
+		return settings, fmt.Errorf("cannot read user file: %w", err)
 	}
 
 	settings.Password, err = readSecretFileAsStringPtr(
@@ -21,7 +21,7 @@ func readOpenVPN() (
 		"/run/secrets/openvpn_password",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading password file: %w", err)
+		return settings, fmt.Errorf("cannot read password file: %w", err)
 	}
 
 	settings.Key, err = readPEMSecretFile(
@@ -29,7 +29,7 @@ func readOpenVPN() (
 		"/run/secrets/openvpn_clientkey",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading client key file: %w", err)
+		return settings, fmt.Errorf("cannot read client key file: %w", err)
 	}
 
 	settings.EncryptedKey, err = readPEMSecretFile(
@@ -53,7 +53,7 @@ func readOpenVPN() (
 		"/run/secrets/openvpn_clientcrt",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading client certificate file: %w", err)
+		return settings, fmt.Errorf("cannot read client certificate file: %w", err)
 	}
 
 	return settings, nil

internal/configuration/sources/secrets/reader.go

@@ -2,17 +2,21 @@ package secrets
 
 import (
 	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/configuration/sources"
 )
 
-type Source struct{}
+var _ sources.Source = (*Reader)(nil)
 
-func New() *Source {
-	return &Source{}
+type Reader struct {
 }
 
-func (s *Source) String() string { return "secret files" }
+func New() *Reader {
+	return &Reader{}
+}
 
-func (s *Source) Read() (settings settings.Settings, err error) {
+func (r *Reader) String() string { return "secret files" }
+
+func (r *Reader) Read() (settings settings.Settings, err error) {
 	settings.VPN, err = readVPN()
 	if err != nil {
 		return settings, err

internal/configuration/sources/secrets/shadowsocks.go

@@ -12,7 +12,7 @@ func readShadowsocks() (settings settings.Shadowsocks, err error) {
 		"/run/secrets/shadowsocks_password",
 	)
 	if err != nil {
-		return settings, fmt.Errorf("reading Shadowsocks password secret file: %w", err)
+		return settings, fmt.Errorf("cannot read Shadowsocks password secret file: %w", err)
 	}
 
 	return settings, nil

internal/configuration/sources/secrets/vpn.go

@@ -9,7 +9,7 @@ import (
 func readVPN() (vpn settings.VPN, err error) {
 	vpn.OpenVPN, err = readOpenVPN()
 	if err != nil {
-		return vpn, fmt.Errorf("reading OpenVPN settings: %w", err)
+		return vpn, fmt.Errorf("cannot read OpenVPN settings: %w", err)
 	}
 
 	return vpn, nil

internal/configuration/sources/source.go

@@ -1,9 +1,9 @@
-package cli
+package sources
 
 import "github.com/qdm12/gluetun/internal/configuration/settings"
 
 type Source interface {
 	Read() (settings settings.Settings, err error)
-	ReadHealth() (health settings.Health, err error)
+	ReadHealth() (settings settings.Health, err error)
 	String() string
 }

internal/constants/openvpn/ciphers.go

@@ -1,11 +1,8 @@
 package openvpn
 
 const (
-	AES128cbc        = "aes-128-cbc"
-	AES192cbc        = "aes-192-cbc"
-	AES256cbc        = "aes-256-cbc"
-	AES128gcm        = "aes-128-gcm"
-	AES192gcm        = "aes-192-gcm"
-	AES256gcm        = "aes-256-gcm"
-	Chacha20Poly1305 = "chacha20-poly1305"
+	AES128cbc = "aes-128-cbc"
+	AES256cbc = "aes-256-cbc"
+	AES128gcm = "aes-128-gcm"
+	AES256gcm = "aes-256-gcm"
 )

internal/constants/providers/providers.go

@@ -3,7 +3,6 @@ package providers
 const (
 	// Custom is the VPN provider name for custom
 	// VPN configurations.
-	Airvpn                = "airvpn"
 	Custom                = "custom"
 	Cyberghost            = "cyberghost"
 	Example               = "example"
@@ -33,7 +32,6 @@ const (
 // All returns all the providers except the custom provider.
 func All() []string {
 	return []string{
-		Airvpn,
 		Cyberghost,
 		Expressvpn,
 		Fastestvpn,

internal/dns/plaintext.go

@@ -1,7 +1,7 @@
 package dns
 
 import (
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/dns/pkg/nameserver"
 )
@@ -12,14 +12,14 @@ func (l *Loop) useUnencryptedDNS(fallback bool) {
 	// Try with user provided plaintext ip address
 	// if it's not 127.0.0.1 (default for DoT)
 	targetIP := settings.ServerAddress
-	if targetIP.Compare(netip.AddrFrom4([4]byte{127, 0, 0, 1})) != 0 {
+	if targetIP != nil && !targetIP.Equal(net.IPv4(127, 0, 0, 1)) { //nolint:gomnd
 		if fallback {
 			l.logger.Info("falling back on plaintext DNS at address " + targetIP.String())
 		} else {
 			l.logger.Info("using plaintext DNS at address " + targetIP.String())
 		}
-		nameserver.UseDNSInternally(targetIP.AsSlice())
-		err := nameserver.UseDNSSystemWide(l.resolvConf, targetIP.AsSlice(), *settings.KeepNameserver)
+		nameserver.UseDNSInternally(targetIP)
+		err := nameserver.UseDNSSystemWide(l.resolvConf, targetIP, *settings.KeepNameserver)
 		if err != nil {
 			l.logger.Error(err.Error())
 		}
@@ -38,8 +38,8 @@ func (l *Loop) useUnencryptedDNS(fallback bool) {
 	} else {
 		l.logger.Info("using plaintext DNS at address " + targetIP.String())
 	}
-	nameserver.UseDNSInternally(targetIP.AsSlice())
-	err = nameserver.UseDNSSystemWide(l.resolvConf, targetIP.AsSlice(), *settings.KeepNameserver)
+	nameserver.UseDNSInternally(targetIP)
+	err = nameserver.UseDNSSystemWide(l.resolvConf, targetIP, *settings.KeepNameserver)
 	if err != nil {
 		l.logger.Error(err.Error())
 	}

internal/dns/setup.go

@@ -43,8 +43,8 @@ func (l *Loop) setupUnbound(ctx context.Context) (
 	}
 
 	// use Unbound
-	nameserver.UseDNSInternally(settings.ServerAddress.AsSlice())
-	err = nameserver.UseDNSSystemWide(l.resolvConf, settings.ServerAddress.AsSlice(),
+	nameserver.UseDNSInternally(settings.ServerAddress)
+	err = nameserver.UseDNSSystemWide(l.resolvConf, settings.ServerAddress,
 		*settings.KeepNameserver)
 	if err != nil {
 		l.logger.Error(err.Error())

internal/firewall/cmd_matcher_test.go

@@ -48,7 +48,7 @@ func (cm *cmdMatcher) String() string {
 	return fmt.Sprintf("path %s, argument regular expressions %v", cm.path, cm.argsRegex)
 }
 
-func newCmdMatcher(path string, argsRegex ...string) *cmdMatcher {
+func newCmdMatcher(path string, argsRegex ...string) *cmdMatcher { //nolint:unparam
 	argsRegexp := make([]*regexp.Regexp, len(argsRegex))
 	for i, argRegex := range argsRegex {
 		argsRegexp[i] = regexp.MustCompile(argRegex)

internal/firewall/enable.go

@@ -21,7 +21,7 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 	if !enabled {
 		c.logger.Info("disabling...")
 		if err = c.disable(ctx); err != nil {
-			return fmt.Errorf("disabling firewall: %w", err)
+			return fmt.Errorf("cannot disable firewall: %w", err)
 		}
 		c.enabled = false
 		c.logger.Info("disabled successfully")
@@ -31,7 +31,7 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 	c.logger.Info("enabling...")
 
 	if err := c.enable(ctx); err != nil {
-		return fmt.Errorf("enabling firewall: %w", err)
+		return fmt.Errorf("cannot enable firewall: %w", err)
 	}
 	c.enabled = true
 	c.logger.Info("enabled successfully")
@@ -41,13 +41,13 @@ func (c *Config) SetEnabled(ctx context.Context, enabled bool) (err error) {
 
 func (c *Config) disable(ctx context.Context) (err error) {
 	if err = c.clearAllRules(ctx); err != nil {
-		return fmt.Errorf("clearing all rules: %w", err)
+		return fmt.Errorf("cannot clear all rules: %w", err)
 	}
 	if err = c.setIPv4AllPolicies(ctx, "ACCEPT"); err != nil {
-		return fmt.Errorf("setting ipv4 policies: %w", err)
+		return fmt.Errorf("cannot set ipv4 policies: %w", err)
 	}
 	if err = c.setIPv6AllPolicies(ctx, "ACCEPT"); err != nil {
-		return fmt.Errorf("setting ipv6 policies: %w", err)
+		return fmt.Errorf("cannot set ipv6 policies: %w", err)
 	}
 	return nil
 }
@@ -98,10 +98,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 	}
 
 	for _, network := range c.localNetworks {
-		if err := c.acceptOutputFromIPToSubnet(ctx, network.InterfaceName, network.IP, network.IPNet, remove); err != nil {
-			return err
-		}
-		if err = c.acceptIpv6MulticastOutput(ctx, network.InterfaceName, remove); err != nil {
+		if err := c.acceptOutputFromIPToSubnet(ctx, network.InterfaceName, network.IP, *network.IPNet, remove); err != nil {
 			return err
 		}
 	}
@@ -113,7 +110,7 @@ func (c *Config) enable(ctx context.Context) (err error) {
 	// Allows packets from any IP address to go through eth0 / local network
 	// to reach Gluetun.
 	for _, network := range c.localNetworks {
-		if err := c.acceptInputToSubnet(ctx, network.InterfaceName, network.IPNet, remove); err != nil {
+		if err := c.acceptInputToSubnet(ctx, network.InterfaceName, *network.IPNet, remove); err != nil {
 			return err
 		}
 	}
@@ -123,14 +120,14 @@ func (c *Config) enable(ctx context.Context) (err error) {
 	}
 
 	if err := c.runUserPostRules(ctx, c.customRulesPath, remove); err != nil {
-		return fmt.Errorf("running user defined post firewall rules: %w", err)
+		return fmt.Errorf("cannot run user defined post firewall rules: %w", err)
 	}
 
 	return nil
 }
 
 func (c *Config) allowVPNIP(ctx context.Context) (err error) {
-	if !c.vpnConnection.IP.IsValid() {
+	if c.vpnConnection.IP == nil {
 		return nil
 	}
 
@@ -138,7 +135,7 @@ func (c *Config) allowVPNIP(ctx context.Context) (err error) {
 	for _, defaultRoute := range c.defaultRoutes {
 		err = c.acceptOutputTrafficToVPN(ctx, defaultRoute.NetInterface, c.vpnConnection, remove)
 		if err != nil {
-			return fmt.Errorf("accepting output traffic through VPN: %w", err)
+			return fmt.Errorf("cannot accept output traffic through VPN: %w", err)
 		}
 	}
 
@@ -165,7 +162,7 @@ func (c *Config) allowInputPorts(ctx context.Context) (err error) {
 			const remove = false
 			err = c.acceptInputToPort(ctx, netInterface, port, remove)
 			if err != nil {
-				return fmt.Errorf("accepting input port %d on interface %s: %w",
+				return fmt.Errorf("cannot accept input port %d on interface %s: %w",
 					port, netInterface, err)
 			}
 		}

internal/firewall/firewall.go

@@ -2,7 +2,7 @@ package firewall
 
 import (
 	"context"
-	"net/netip"
+	"net"
 	"sync"
 
 	"github.com/qdm12/gluetun/internal/models"
@@ -27,7 +27,7 @@ type Config struct { //nolint:maligned
 	enabled           bool
 	vpnConnection     models.Connection
 	vpnIntf           string
-	outboundSubnets   []netip.Prefix
+	outboundSubnets   []net.IPNet
 	allowedInputPorts map[uint16]map[string]struct{} // port to interfaces set mapping
 	stateMutex        sync.Mutex
 }

internal/firewall/iptables.go

@@ -5,7 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"net/netip"
+	"net"
 	"os"
 	"os/exec"
 	"strings"
@@ -95,11 +95,14 @@ func (c *Config) setIPv4AllPolicies(ctx context.Context, policy string) error {
 	default:
 		return fmt.Errorf("%w: %s", ErrPolicyUnknown, policy)
 	}
-	return c.runIptablesInstructions(ctx, []string{
+	if err := c.runIptablesInstructions(ctx, []string{
 		"--policy INPUT " + policy,
 		"--policy OUTPUT " + policy,
 		"--policy FORWARD " + policy,
-	})
+	}); err != nil {
+		return err
+	}
+	return nil
 }
 
 func (c *Config) acceptInputThroughInterface(ctx context.Context, intf string, remove bool) error {
@@ -108,8 +111,9 @@ func (c *Config) acceptInputThroughInterface(ctx context.Context, intf string, r
 	))
 }
 
-func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
-	destination netip.Prefix, remove bool) error {
+func (c *Config) acceptInputToSubnet(ctx context.Context, intf string, destination net.IPNet, remove bool) error {
+	isIP4Subnet := destination.IP.To4() != nil
+
 	interfaceFlag := "-i " + intf
 	if intf == "*" { // all interfaces
 		interfaceFlag = ""
@@ -118,7 +122,7 @@ func (c *Config) acceptInputToSubnet(ctx context.Context, intf string,
 	instruction := fmt.Sprintf("%s INPUT %s -d %s -j ACCEPT",
 		appendOrDelete(remove), interfaceFlag, destination.String())
 
-	if destination.Addr().Is4() {
+	if isIP4Subnet {
 		return c.runIptablesInstruction(ctx, instruction)
 	}
 	if c.ip6Tables == "" {
@@ -145,7 +149,8 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 	instruction := fmt.Sprintf("%s OUTPUT -d %s -o %s -p %s -m %s --dport %d -j ACCEPT",
 		appendOrDelete(remove), connection.IP, defaultInterface, connection.Protocol,
 		connection.Protocol, connection.Port)
-	if connection.IP.Is4() {
+	isIPv4 := connection.IP.To4() != nil
+	if isIPv4 {
 		return c.runIptablesInstruction(ctx, instruction)
 	} else if c.ip6Tables == "" {
 		return fmt.Errorf("accept output to VPN server: %w", ErrNeedIP6Tables)
@@ -155,15 +160,8 @@ func (c *Config) acceptOutputTrafficToVPN(ctx context.Context,
 
 // Thanks to @npawelek.
 func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
-	intf string, sourceIP netip.Addr, destinationSubnet netip.Prefix, remove bool) error {
-	doIPv4 := sourceIP.Is4() && destinationSubnet.Addr().Is4()
-	doIPv6 := sourceIP.Is6() && destinationSubnet.Addr().Is6()
-	if !doIPv4 && !doIPv6 {
-		c.logger.Debug(fmt.Sprintf(
-			"source IP address %s and destination subnet %s are not of the same IP family, skipping...",
-			sourceIP, destinationSubnet))
-		return nil
-	}
+	intf string, sourceIP net.IP, destinationSubnet net.IPNet, remove bool) error {
+	doIPv4 := sourceIP.To4() != nil && destinationSubnet.IP.To4() != nil
 
 	interfaceFlag := "-o " + intf
 	if intf == "*" { // all interfaces
@@ -181,18 +179,6 @@ func (c *Config) acceptOutputFromIPToSubnet(ctx context.Context,
 	return c.runIP6tablesInstruction(ctx, instruction)
 }
 
-// NDP uses multicast address (theres no broadcast in IPv6 like ARP uses in IPv4).
-func (c *Config) acceptIpv6MulticastOutput(ctx context.Context,
-	intf string, remove bool) error {
-	interfaceFlag := "-o " + intf
-	if intf == "*" { // all interfaces
-		interfaceFlag = ""
-	}
-	instruction := fmt.Sprintf("%s OUTPUT %s -d ff02::1:ff/104 -j ACCEPT",
-		appendOrDelete(remove), interfaceFlag)
-	return c.runIP6tablesInstruction(ctx, instruction)
-}
-
 // Used for port forwarding, with intf set to tun.
 func (c *Config) acceptInputToPort(ctx context.Context, intf string, port uint16, remove bool) error {
 	interfaceFlag := "-i " + intf
@@ -259,7 +245,7 @@ func (c *Config) runUserPostRules(ctx context.Context, filepath string, remove b
 		case ipv4:
 			err = c.runIptablesInstruction(ctx, rule)
 		case c.ip6Tables == "":
-			err = fmt.Errorf("running user ip6tables rule: %w", ErrNeedIP6Tables)
+			err = fmt.Errorf("cannot run user ip6tables rule: %w", ErrNeedIP6Tables)
 		default: // ipv6
 			err = c.runIP6tablesInstruction(ctx, rule)
 		}

internal/firewall/outboundsubnets.go

@@ -3,18 +3,18 @@ package firewall
 import (
 	"context"
 	"fmt"
-	"net/netip"
+	"net"
 
 	"github.com/qdm12/gluetun/internal/subnet"
 )
 
-func (c *Config) SetOutboundSubnets(ctx context.Context, subnets []netip.Prefix) (err error) {
+func (c *Config) SetOutboundSubnets(ctx context.Context, subnets []net.IPNet) (err error) {
 	c.stateMutex.Lock()
 	defer c.stateMutex.Unlock()
 
 	if !c.enabled {
 		c.logger.Info("firewall disabled, only updating allowed subnets internal list")
-		c.outboundSubnets = make([]netip.Prefix, len(subnets))
+		c.outboundSubnets = make([]net.IPNet, len(subnets))
 		copy(c.outboundSubnets, subnets)
 		return nil
 	}
@@ -28,13 +28,13 @@ func (c *Config) SetOutboundSubnets(ctx context.Context, subnets []netip.Prefix)
 
 	c.removeOutboundSubnets(ctx, subnetsToRemove)
 	if err := c.addOutboundSubnets(ctx, subnetsToAdd); err != nil {
-		return fmt.Errorf("setting allowed outbound subnets: %w", err)
+		return fmt.Errorf("cannot set allowed outbound subnets: %w", err)
 	}
 
 	return nil
 }
 
-func (c *Config) removeOutboundSubnets(ctx context.Context, subnets []netip.Prefix) {
+func (c *Config) removeOutboundSubnets(ctx context.Context, subnets []net.IPNet) {
 	const remove = true
 	for _, subNet := range subnets {
 		for _, defaultRoute := range c.defaultRoutes {
@@ -49,7 +49,7 @@ func (c *Config) removeOutboundSubnets(ctx context.Context, subnets []netip.Pref
 	}
 }
 
-func (c *Config) addOutboundSubnets(ctx context.Context, subnets []netip.Prefix) error {
+func (c *Config) addOutboundSubnets(ctx context.Context, subnets []net.IPNet) error {
 	const remove = false
 	for _, subnet := range subnets {
 		for _, defaultRoute := range c.defaultRoutes {

internal/firewall/ports.go

@@ -36,11 +36,10 @@ func (c *Config) SetAllowedPort(ctx context.Context, port uint16, intf string) (
 
 	const remove = false
 	if err := c.acceptInputToPort(ctx, intf, port, remove); err != nil {
-		return fmt.Errorf("allowing input to port %d through interface %s: %w",
+		return fmt.Errorf("cannot allow input to port %d through interface %s: %w",
 			port, intf, err)
 	}
 	netInterfaces[intf] = struct{}{}
-	c.allowedInputPorts[port] = netInterfaces
 
 	return nil
 }
@@ -70,7 +69,7 @@ func (c *Config) RemoveAllowedPort(ctx context.Context, port uint16) (err error)
 	for netInterface := range interfacesSet {
 		err := c.acceptInputToPort(ctx, netInterface, port, remove)
 		if err != nil {
-			return fmt.Errorf("removing allowed port %d on interface %s: %w",
+			return fmt.Errorf("cannot remove allowed port %d on interface %s: %w",
 				port, netInterface, err)
 		}
 		delete(interfacesSet, netInterface)

internal/firewall/support.go

@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"math/rand"
 	"os/exec"
-	"sort"
 	"strings"
 
 	"github.com/qdm12/golibs/command"
@@ -21,7 +20,7 @@ var (
 
 func checkIptablesSupport(ctx context.Context, runner command.Runner,
 	iptablesPathsToTry ...string) (iptablesPath string, err error) {
-	iptablesPathToUnsupportedMessage := make(map[string]string, len(iptablesPathsToTry))
+	var lastUnsupportedMessage string
 	for _, pathToTest := range iptablesPathsToTry {
 		ok, unsupportedMessage, err := testIptablesPath(ctx, pathToTest, runner)
 		if err != nil {
@@ -30,35 +29,17 @@ func checkIptablesSupport(ctx context.Context, runner command.Runner,
 			iptablesPath = pathToTest
 			break
 		}
-		iptablesPathToUnsupportedMessage[pathToTest] = unsupportedMessage
+
+		lastUnsupportedMessage = unsupportedMessage
 	}
 
-	if iptablesPath != "" {
-		// some paths may be unsupported but that does not matter
-		// since we found one working.
-		return iptablesPath, nil
+	if iptablesPath == "" { // all iptables to try failed
+		return "", fmt.Errorf("%w: from %s: last error is: %s",
+			ErrIPTablesNotSupported, strings.Join(iptablesPathsToTry, ", "),
+			lastUnsupportedMessage)
 	}
 
-	allArePermissionDenied := true
-	allUnsupportedMessages := make(sort.StringSlice, 0, len(iptablesPathToUnsupportedMessage))
-	for iptablesPath, unsupportedMessage := range iptablesPathToUnsupportedMessage {
-		if !isPermissionDenied(unsupportedMessage) {
-			allArePermissionDenied = false
-		}
-		unsupportedMessage = iptablesPath + ": " + unsupportedMessage
-		allUnsupportedMessages = append(allUnsupportedMessages, unsupportedMessage)
-	}
-
-	allUnsupportedMessages.Sort() // predictable order for tests
-
-	if allArePermissionDenied {
-		// If the error is related to a denied permission for all iptables path,
-		// return an error describing what to do from an end-user perspective.
-		return "", fmt.Errorf("%w: %s", ErrNetAdminMissing, strings.Join(allUnsupportedMessages, "; "))
-	}
-
-	return "", fmt.Errorf("%w: errors encountered are: %s",
-		ErrIPTablesNotSupported, strings.Join(allUnsupportedMessages, "; "))
+	return iptablesPath, nil
 }
 
 func testIptablesPath(ctx context.Context, path string,
@@ -75,6 +56,14 @@ func testIptablesPath(ctx context.Context, path string,
 		"-A", "OUTPUT", "-o", testInterfaceName, "-j", "DROP")
 	output, err := runner.Run(cmd)
 	if err != nil {
+		if isPermissionDenied(output) {
+			// If the error is related to a denied permission,
+			// return an error describing what to do from an end-user
+			// perspective. This is a critical error and likely
+			// applies to all iptables.
+			criticalErr = fmt.Errorf("%w: %s", ErrNetAdminMissing, output)
+			return false, "", criticalErr
+		}
 		unsupportedMessage = fmt.Sprintf("%s (%s)", output, err)
 		return false, unsupportedMessage, nil
 	}
@@ -95,6 +84,10 @@ func testIptablesPath(ctx context.Context, path string,
 	cmd = exec.CommandContext(ctx, path, "-L", "INPUT")
 	output, err = runner.Run(cmd)
 	if err != nil {
+		if isPermissionDenied(output) {
+			criticalErr = fmt.Errorf("%w: %s", ErrNetAdminMissing, output)
+			return false, "", criticalErr
+		}
 		unsupportedMessage = fmt.Sprintf("%s (%s)", output, err)
 		return false, unsupportedMessage, nil
 	}
@@ -116,6 +109,10 @@ func testIptablesPath(ctx context.Context, path string,
 	cmd = exec.CommandContext(ctx, path, "--policy", "INPUT", inputPolicy)
 	output, err = runner.Run(cmd)
 	if err != nil {
+		if isPermissionDenied(output) {
+			criticalErr = fmt.Errorf("%w: %s", ErrNetAdminMissing, output)
+			return false, "", criticalErr
+		}
 		unsupportedMessage = fmt.Sprintf("%s (%s)", output, err)
 		return false, unsupportedMessage, nil
 	}