# vppn: Virtual Pretty Private Network

## Roadmap

* `node` package
  * rename `peerRepo` to `routingTable`
  * create router type with `Get(ip) *peer` and `Mediator() *peer` methods
  * connReader / Writer should have access to the peerRepo
* Use default port 456
* Remove signing key from hub
* Peer: UDP hole-punching
* Peer: local peer discovery - part of RoutingProcessor
* Peer: update hub w/ latest port on startup

## Learnings

* Encryption / decryption is 20x faster than signing/opening.
* Allowing out-of order packets is massively important for throughput with TCP

## Principles

* Creates an IPv4/24 network with a maximum of 254 peers. (1-254)
* Simple setup: via setup link from the hub.
* Each peer has full network state replicated from the hub.

## Routing

* Routing is different for public vs non-public peers
  * Public: routes are initialized via incoming ping requests
  * NonPub: routes are initialized via incoming ping responses

A non-public peer needs to maintain connections with every public peer.

* Sending:
  * Public: send to address
  * Non-public: send to a mediator

* Pings:
  * Servers don't need to ping
  * Clients need to ping all public and local peers to keep connections open

## Hub Server Configuration

```
# Create user.
adduser user

# Enable ssh.
cp -r ~/.ssh /home/user/
chown -R user:user /home/user/.ssh

```

Upload `hub` executable:

```
scp hub user@<remote>:~/
```

Create systemd file in `/etc/systemd/system/hub.service

```
Description=hub
Requires=network.target

[Service]
AmbientCapabilities=CAP_NET_BIND_SERVICE
Type=simple
User=user
WorkingDirectory=/home/user/
ExecStart=/home/user/hub -listen <addr>:https -secure=true -root-dir=/home/user
Restart=always
RestartSec=8
TimeoutStopSec=24

[Install]
WantedBy=default.target
```

Add and start the hub server:

```
systemctl daemon-reload
systemctl start hub
```

Get initial password from logs:

```
journalctl -f -u hub -n 100
```

Sign-in and configure.

## Peer Configuration

Install the binary somewhere, for example `~/bin/vppn`.

Create systemd file in `/etc/systemd/system/vppn.service`.


```
Description=vppn
Requires=network.target

[Service]
AmbientCapabilities=CAP_NET_BIND_SERVICE CAP_NET_ADMIN
Type=simple
User=user
WorkingDirectory=/home/user/
ExecStart=/home/user/vppn -name vppn
Restart=always
RestartSec=8
TimeoutStopSec=24

[Install]
WantedBy=default.target
```