# wgautomesh

`wgautomesh` is a simple utility to help configure a full-mesh wireguard network.
It does not assume that all nodes have a publicly reachable address.  It uses a
gossip protocol to broadcast the endpoint addresses nodes use to talk to one
another. This way, even if nodes A and B are not able to communicate directly
initially (both behind NAT), if they can both communicate with node C then they
will indirectly be able to know each other's NAT-ed address and port. They will
then try to connect to one another using those addresses, which should allow
NAT hole punching.

Features:

- does not assume all nodes are publicly reachable
- configuration very similar to `wg-quick`: each node needs a list of the credentials of all other nodes in the mesh
- ultra simple encrypted gossip protocol over UDP (bincode encoding + xsalsa20poly1305 symmetric encryption)
- automatic discovery of nodes in a same LAN using UDP broadcast (if enabled, nodes will prefer connecting to one another using their LAN IP addresses when available)
- can automatically open ports in your router using IGD/UPnP
- saves to disk known addresses of peers so that they can be reused on restart (usefull if all addresses have changed and the ones in the config file are no longer relevant)

Remarks/limitations:

- `wgautomesh` does not create a wireguard interface, it assumes it exists and merely configures the peers attached to it
- `wgautomesh` only tries to establish connectivity to the peers specified in its config file,
it does not provide facilities for dynamically adding more peers like many wireguard configuration tools do.

`wgautomesh` was built for Deuxfleurs to integrate with our automated NixOS-based configuration management system.
`wgautomesh` is packaged in NixOS since version 23.05.
Configuration options are listed [here](https://search.nixos.org/options?from=0&size=50&sort=relevance&query=wgautomesh)
and closely mirror the structure of the configuration file described below.

### Sample configuration file

```toml
# The Wireguard interface to control.
interface = "wg0"

# The port wgautomesh will use to communicate from node to node.  Wgautomesh
# gossip communications occur inside the wireguard mesh network.
gossip_port = 1666

# Enable discovery of other wgautomesh nodes on the same LAN using UDP broadcast.
lan_discovery = true

# Enables UPnP/IGD forwarding of an external port to the Wireguard listening port
# on this node, for compatible routers/gateways.
upnp_forward_external_port = 33723

# The path to a file that contains the encryption secret wgautomesh uses to
# communicate.  This secret can be any arbitrary utf-8 string.  The following
# command can be used to generate a new secret:
#     openssl rand -base64 32
gossip_secret_file = "/var/lib/wgautomesh/gossip_secret"

# The path to a file that wgautomesh can write to, to save the endpoint addresses
# it successfully used to connect to other nodes in the mesh.  These addresses
# are used in conjunction with the endpoint addresses specified below in the
# `[[peers]]` section when trying to establish connectivity.
persist_file = "/var/lib/wgautomesh/state"

[[peers]]
pubkey = "7Nm7pMmyS7Nts1MB+loyD8u84ODxHPTkDu+uqQR6yDk="
address = "10.14.1.2"
endpoint = "77.207.15.215:33722"

[[peers]]
pubkey = "lABn/axzD1jkFulX8c+K3B3CbKXORlIMDDoe8sQVxhs="
address = "10.14.1.3"
endpoint = "77.207.15.215:33723"

[[peers]]
pubkey = "XLOYoMXF+PO4jcgfSVAk+thh4VmWx0wzWnb0xs08G1s="
address = "10.14.4.1"
endpoint = "bitfrost.fiber.shirokumo.net:33734"

[[peers]]
pubkey = "smBQYUS60JDkNoqkTT7TgbpqFiM43005fcrT6472llI="
address = "10.14.2.33"
endpoint = "82.64.238.84:33733"

[[peers]]
pubkey = "m9rLf+233X1VColmeVrM/xfDGro5W6Gk5N0zqcf32WY="
address = "10.14.3.1"
```