## WireGuard VPN with 2 or more subnets

Date [ 2019-02-14 ] Tags [ wireguard vpn ]

I wanted to create a WireGuard VPN with 2 subnets in different physical places, each with their own server. I couldn’t find an example how to do that, so I wrote this one.

## Introduction

I’m going to use the IP range `fd69::/48` for the VPN, `fd69:0:0:1::/64` for subnet 1 and `fd69:0:0:2::/64` for subnet 2. I’m going to call the server of subnet 1 `server1`, its first client `client1a`, the second one `client1b` and so on.

All clients in subnet 1 will connect to `server1` and all clients in subnet 2 will connect to `server2`. `server1` and `server2` will be connected. If `client1a` wants to connect to `client2a`, the route will be: `client1a → server1 → server2 → client2a`.

## Preparations

Install WireGuard, create `/etc/wireguard` and generate a key-pair on each participating peer.

    mkdir /etc/wireguard
    cd /etc/wireguard
    umask 077
    wg genkey | tee privatekey | wg pubkey > publickey

## Configure servers

`server1:/etc/wireguard/wg0.conf`:

    # This peer
    [Interface]
    Address = fd69:0:0:1::1/48
    PrivateKey = <PRIVATE KEY OF server1>
    ListenPort = 51820

    # Server of subnet 2
    [Peer]
    PublicKey = <PUBLIC KEY OF server2>
    Endpoint = server2:51820
    AllowedIPs = fd69:0:0:2::/64

    # Clients of subnet 1
    [Peer]
    PublicKey = <PUBLIC KEY OF client1a>
    AllowedIPs = fd69:0:0:1::a/128

    [Peer]
    PublicKey = <PUBLIC KEY OF client1b>
    AllowedIPs = fd69:0:0:1::b/128

`server2:/etc/wireguard/wg0.conf`:

    # This peer
    [Interface]
    Address = fd69:0:0:2::1/48
    PrivateKey = <PRIVATE KEY OF server2>
    ListenPort = 51820

    # Server of subnet 1
    [Peer]
    PublicKey = <PUBLIC KEY OF server1>
    Endpoint = server1:51820
    AllowedIPs = fd69:0:0:1::/64

    # Clients of subnet 2
    [Peer]
    PublicKey = <PUBLIC KEY OF client2a>
    AllowedIPs = fd69:0:0:2::a/128

## Configure clients

`client1a:/etc/wireguard/wg0.conf`:

    [Interface]
    Address = fd69:0:0:1::a/48
    PrivateKey = <PRIVATE KEY OF client1a>

    [Peer]
    PublicKey = <PUBLIC KEY OF server1>
    Endpoint = server1:51820
    AllowedIPs = fd69::/48
    PersistentKeepalive = 25

`client1b:/etc/wireguard/wg0.conf`:

    [Interface]
    Address = fd69:0:0:1::b/48
    PrivateKey = <PRIVATE KEY OF client1b>

    [Peer]
    PublicKey = <PUBLIC KEY OF server1>
    Endpoint = server1:51820
    AllowedIPs = fd69::/48
    PersistentKeepalive = 25

`client2a:/etc/wireguard/wg0.conf`:

    [Interface]
    Address = fd69:0:0:2::a/48
    PrivateKey = <PRIVATE KEY OF client2a>

    [Peer]
    PublicKey = <PUBLIC KEY OF server2>
    Endpoint = server1:51820
    AllowedIPs = fd69::/48
    PersistentKeepalive = 25

The `AllowedIPs` setting acts as a routing table. When a peer tries to send a packet to an IP, it will check `AllowedIPs`, and if the IP appears in the list, it will send it through the WireGuard interface.

The `PersistentKeepalive` setting ensures that the connection is maintained and that the peer continues to be reachable, even behind a NAT.

## Start VPN

Run `wg-quick up wg0` on each peer.

## Further reading

The article How to easily configure WireGuard by Stavros Korokithakis helped me a great deal in understanding WireGuard.

## Using AsciiDoc(tor) with Gitea

Date [ 2019-01-26 ] Tags [ asciidoc gitea ]

In this blogpost I describe what I did to get AsciiDoc support into Gitea. If you want more than syntax highlighting and basic formatting, Gitea has to be patched unfortunately(this issue has already been reported). But I think most people will only need to edit 1 configuration file and are done.

## Asciidoctor or AsciiDoc?

Asciidoctor has inbuilt support for highlight.js, the solution Gitea uses and is therefore the best choice in most scenarios. If you can’t or don’t want to use it you can use AsciiDoc.

Add the following section to `conf/app.ini` in your Gitea path. The change causes `.adoc` files to be rendered with asciidoctor.

    [markup.asciidoc]
    ENABLED = true
    ; List of file extensions that should be rendered by an external command
    FILE_EXTENSIONS = .adoc,.asciidoc
    ; External command to render all matching extensions
    RENDER_COMMAND = "asciidoctor --backend=html5 --no-header-footer --attribute source-highlighter=highlightjs --out-file=- -"
    ; Don't pass the file on STDIN, pass the filename as argument instead.
    IS_INPUT_FILE = false

If you want to use asciidoc instead the command would be: `asciidoc --backend=xhtml11 --no-header-footer --attribute source-highlighter=highlight --out-file=- -`. I would choose the `xhtml11` backend because it is the only one that encloses code snippets with `<code>` tags. Instead of highlight you can use source-highlight or Pygments.

If you use asciidoctor and don’t need tables or other fancy stuff you’re now done! If you use asciidoc, you’ll have to patch Gitea to get syntax highlighting.

## Patching Gitea

The sanitizer strips almost all attributes from HTML-tags, as a security precaution. I’ve added exceptions for:

- `class` attributes on all the tags Asciidoctor introduces,

- Numerous attributes on `table` tags,

- `align` and `valign` on `td` tags,

- `style` attributes on `span` tags, but only if they contain nothing more than color and font definitions.

If you use Asciidoctor with highlight.js output, you don’t need to allow `style` attributes, if you don’t use tables you can omit the lines that deal with them and the `class` exception is only useful if you add custom CSS to use them.

Apply the patch with `patch -p1 < gitea_relax-sanitizer.patch`.

    diff -ur a/modules/markup/sanitizer.go b/modules/markup/sanitizer.go
    --- a/modules/markup/sanitizer.go   2019-01-26 16:04:56.014108339 +0100
    +++ b/modules/markup/sanitizer.go   2019-01-26 16:03:21.776401012 +0100
    @@ -38,6 +38,16 @@

            // Custom URL-Schemes
            sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
    +       // Allow style on span tags
    +       sanitizer.policy.AllowAttrs("style").Matching(regexp.MustCompile(`^(background-)?color:[^;]+(; ?font[^;]+)?;?$`)).OnElements("span")
    +
    +       // Allow class attribute
    +       sanitizer.policy.AllowAttrs("class").OnElements("code", "pre", "span", "div", "p", "table", "td")
    +
    +       // Allow table attributes
    +       sanitizer.policy.AllowAttrs("width", "frame", "rules", "cellspacing", "cellpadding").OnElements("table")
    +       sanitizer.policy.AllowAttrs("width").OnElements("col")
    +       sanitizer.policy.AllowAttrs("align", "valign").OnElements("td")
        })
     }

## Tables without borders

I used tables without borders in a manpage I wrote for the list of options. Gitea insist on drawing borders around them, so I had to create a custom CSS snippet.

In your Gitea directory, create `custom/templates/custom/header.tmpl`.

    <style>
        /* Additions for asciidoc */
        .markdown:not(code) table.frame-none
        {
            border: 0 !important;
        }
        .markdown:not(code) table.grid-none *
        {
            border: 0 !important;
        }
    </style>