From 799c111fb47e03b693074374210c8c9c938bc8e7 Mon Sep 17 00:00:00 2001
From: Paul Buetow <paul@buetow.org>
Date: Fri, 18 Apr 2025 23:53:53 +0300
Subject: can generate keys

---
 .gitignore                |  1 +
 wireguardmeshgenerator.rb | 82 ++++++++++++++++++++++++++++++++++-------------
 2 files changed, 61 insertions(+), 22 deletions(-)

diff --git a/.gitignore b/.gitignore
index 849ddff..fa29eef 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 dist/
+keys/
diff --git a/wireguardmeshgenerator.rb b/wireguardmeshgenerator.rb
index ae7ddd4..2a76e73 100644
--- a/wireguardmeshgenerator.rb
+++ b/wireguardmeshgenerator.rb
@@ -1,7 +1,8 @@
-#!/usr/bin/ruby
+#!/usr/bin/env ruby
 
 require 'fileutils'
 
+WIREGUARD_TOOL = '/usr/bin/wg'.freeze
 HOSTS = {
   f0: { lan: { domain: 'lan.buetow.org', ip: '192.168.1.130' },
         wg0: { domain: 'wg0.buetow.org', ip: '192.168.2.130' } },
@@ -17,45 +18,82 @@ HOSTS = {
         wg0: { domain: 'wg0.buetow.org', ip: '192.168.2.122' } }
 }.freeze
 
-PeerSnippet = Struct.new(:description, :public_key, :preshared_key, :allowed_ips) do
+# Generates Wireguard keys and config files for each host
+class KeyTool
+  def initialize(myself)
+    keys_dir = "keys/#{myself}/"
+    FileUtils.mkdir_p(keys_dir) unless Dir.exist?(keys_dir)
+
+    @pubkey_path = "#{keys_dir}/pubkey"
+    @privkey_path = "#{keys_dir}/privkey"
+    @preshared_path = "#{keys_dir}/preshared"
+
+    generate! if !File.exist?(@pubkey_path) ||
+                 !File.exist?(@privkey_path) ||
+                 !File.exist?(@preshared_path)
+  end
+
+  def pub = File.read(@pubkey_path).strip
+  def priv = File.read(@privkey_path).strip
+  def preshared = File.read(@preshared_path).strip
+
+  private
+
+  def generate! = gen_privpub! && genpsk!
+  def genpsk! = File.write(@preshared_path, `#{WIREGUARD_TOOL} genpsk`)
+
+  def gen_privpub!
+    privkey = IO.popen("#{WIREGUARD_TOOL} genkey", 'r+', &:read)
+    IO.popen("#{WIREGUARD_TOOL} pubkey", 'r+') do |io|
+      io.puts(privkey)
+      io.close_write
+      File.write(@privkey_path, privkey)
+      File.write(@pubkey_path, io.read)
+    end
+  end
+end
+
+PeerSnippet = Struct.new(:myself, :domain, :allowed_ips) do
   def to_s
+    keys = KeyTool.new(myself)
     <<~PEER_CONFIG
       [Peer]
-      # #{description}
-      PublicKey = #{public_key}
-      PresharedKey = #{preshared_key}
-      AllowedIPs = #{allowed_ips}
+      # #{myself}.#{domain}
+      PublicKey = #{keys.pub}
+      PresharedKey = #{keys.preshared}
+      AllowedIPs = #{allowed_ips}/32
     PEER_CONFIG
   end
 end
 
 WireguardConfig = Struct.new(:myself, :hosts) do
-  @peers = hosts.map do |name, data|
-    PeerSnippet.new("#{name}.#{data[:wg0][:domain]}",
-                    :PUB_KEY, :PRESHARED_KEY, "#{data[:wg0][:ip]}/32")
-  end
-
   def to_s
+    peers = hosts.reject { _1 == myself }.map do |hostname, data|
+      PeerSnippet.new(hostname, data[:wg0][:domain], data[:wg0][:ip])
+    end
+
+    keys = KeyTool.new(myself)
     <<~CONFIG
       [Interface]
+      # #{myself}.#{hosts[myself][:wg0][:domain]}
       Address = #{hosts[myself][:wg0][:ip]}
-      PrivateKey = #{private_key}
+      PrivateKey = #{keys.priv}
+      PresharedKey = #{keys.preshared}
 
-      #{@peers.map(&:to_s).join("\n")}
+      #{peers.map(&:to_s).join("\n")}
     CONFIG
   end
-
-  private
-
-  def private_key = 'PRIVATE_KEY'
 end
 
-HOSTS.each_key do |name|
-  config_dir = "dist/#{name}/etc/wireguard"
+HOSTS.each_key do |hostname|
+  raise 'Wireguard tool not found' unless File.exist?(WIREGUARD_TOOL)
+
+  config_dir = "dist/#{hostname}/etc/wireguard"
+  key_dir = "keys/#{hostname}/"
   config_path = "#{config_dir}/wg0.conf"
-  FileUtils.mkdir_p(config_dir) unless Dir.exist?(config_dir)
+  [config_dir, key_dir].each { FileUtils.mkdir_p(_1) unless Dir.exist?(_1) }
 
-  wg0 = WireguardConfig.new(name, HOSTS)
-  puts "Generating config for #{name} at #{config_path}"
+  wg0 = WireguardConfig.new(hostname, HOSTS)
+  puts "Generating config for #{hostname} at #{config_path}"
   File.write(config_path, wg0.to_s)
 end
-- 
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