Add documentation

README.md

@@ -5,3 +5,90 @@ Converts and adds IPv4- to IPv6-Adresses and AllowedIP-Entries for wireguard-int
 
 <br>
 
+<!-- TOC -->
+- [1. Overview](#1-overview)
+- [2. Install](#2-install)
+    - [2.1. From Binary](#21-from-binary)
+    - [2.2. From sources](#22-from-sources)
+- [3. Setup](#3-setup)
+    - [3.1. Environment](#31-environment)
+    - [3.2. Examples](#32-examples)
+- [4. License](#4-license)
+<!-- /TOC -->
+
+<br>
+
+# 1. Overview
+
+The program will convert IPv4-only wireguard-interfaces to IPv6. It converts and adds the Address of the Interface and AllowedIPs-Entries with optional filters.
+
+IPv6-Adresses are generated based on the IPv4-Adress.
+
+Beware: This program needs `NET_ADMIN` privileges for setting Adresses and to access the wireguard-daemon.
+
+<br>
+
+# 2. Install
+
+## 2.1. From Binary
+
+1. Download the appripriate binary for your system from the Release-page (or build from sources)
+2. Save at an appropriate location e.g. `/usr/bin/local/wg-ipv6-converter`
+3. Make executeable: `chmod +x /usr/bin/local/wg-ipv6-converter`
+
+<br>
+
+## 2.2. From sources
+
+Clone the repository and compile using `go build ./cmd/app`
+
+<br>
+
+# 3. Setup
+## 3.1. Environment
+
+Variable|Description|Default
+-|-|-
+`INTERFACE`*        | Wireguard-Interface Name                  |
+`IPV6_FORMAT`       | Format to use for converting v4 to v6 <br> The CIDR-Mask gets translated using 128 - 24 - Mask <br> e.g. `10.0.100.5/16` -> `fc12::0a00:6405/96`   | `fc12::%02x%02x:%02x%02x/%d`
+`RECHECK_INTERVAL`  | Interval in seconds to recheck AllowedIPs entries in case something changed  | 300
+
+*\* Required*
+
+<br>
+
+## 3.2. Examples
+
+### 3.2.1.  Netbird
+
+Netbird is at the moment only IPv4-compatible, with this program running where necessary, some basic IPv6-setup can be archieved.
+
+```bash
+INTERFACE="wt0" ./wg-ipv6-converter
+```
+Or using a systemd-service based on the example:
+```bash
+[Unit]
+Description=WireGuard IPv6 converter for netbird
+BindsTo=netbird.service
+
+[Service]
+Type=simple
+ExecStart=/usr/local/bin/wg-ipv6-converter
+Restart=always
+RestartSec=60
+StandardOutput=syslog
+StandardError=syslog
+
+Environment="INTERFACE=wt0"
+
+[Install]
+WantedBy=multi-user.target
+```
+
+<br>
+
+# 4. License
+
+This project is licenced under GPLv3.  
+See [LICENSE](LICENSE) for more details.