add small tutorial how to compile and install fastd

Signed-off-by: Marek Küthe <m.k@mk16.de>

docs/tunneling/fastd-compile-install.md

@@ -0,0 +1,60 @@
+
+# Compile and install fastd
+
+The fastd compilation process is documented at [Building fastd](https://fastd.readthedocs.io/en/stable/devel/building.html. This is only a brief guide. For reference, the official fastd documentation should be used.
+
+## Preparation
+
+The first thing to do is to install the appropriate dependencies. On Debian you can do this with the following command:
+```
+sudo apt install build-essential meson bison libuecc-dev libcap-dev libjson-c-dev libssl-dev libmnl-dev libsodium-dev clang-format
+```
+
+After that you can clone the Git repository. GitHub requires an IPv4 clearnet connection.
+```
+git clone https://github.com/NeoRaider/fastd.git
+```
+
+## Compilation
+
+After that you can prepare the compilation:
+```
+meson setup fastd fastd-build -Dbuildtype=release -Db_lto=true -Dcapabilities=enabled -Doffload_l2tp=enabled
+```
+`-Db_lto=true` activates link-time optimizations. `-Dcapabilities=enabled` enables the option that fastd can later negotiate capabilities with its peer accordingly. `-Doffload_l2tp=enabled` enables the option to later offload L2TP connections in fastd to the kernel and thus increase speed.
+
+In addition, the `-Doptimization=3` flag can be used to perform strong optimizations. The flag `-Dmethod_cipher-test=enabled` can be used to use the `cipher-test` method in fastd.
+
+
+After that you can change to the build directory and compile fastd:
+```
+cd fastd-build
+ninja
+```
+
+To install fastd you can use the following command:
+```
+sudo ninja install
+```
+
+## Installation
+
+If you want to use fastd with Systemd, you can create a unit in the file `/lib/systemd/system/fastd@.service`:
+```
+[Unit]
+Description=Fast and Secure Tunnelling Daemon (connection %I)
+After=network.target
+
+[Service]
+Type=notify
+ExecStart=/usr/local/bin/fastd --syslog-level info --syslog-ident fastd@%I -c /etc/fastd/%I/fastd.conf
+ExecReload=/bin/kill -HUP $MAINPID
+
+[Install]
+WantedBy=multi-user.target
+```
+
+After that you can load the new unit:
+```
+systemctl daemon-reload
+```

docs/tunneling/index.md

@@ -2,6 +2,7 @@
 # Tunneling
 
 - [fastd](fastd)
+- [Compile and install fastd](fastd)
 - [WireGuard](wireguard)
 - [OpenVPN](openvpn)
 - [IP tunnel](iptunnel)