From 3a2d1481f28f9c2c43e205dca04d8f6aca43bdb8 Mon Sep 17 00:00:00 2001
From: Nico Schottelius <nico@nico-notebook.schottelius.org>
Date: Sat, 5 Dec 2020 15:05:12 +0100
Subject: [PATCH] add support for prefix generation

---
 ipv6ula/forms.py                        |  5 ++++
 ipv6ula/templates/ipv6ula/base.html     |  5 +++-
 ipv6ula/templates/ipv6ula/ula_form.html | 21 +++++++++++++---
 ipv6ula/templates/ipv6ula/ula_list.html | 10 +++++++-
 ipv6ula/urls.py                         |  1 +
 ipv6ula/utils.py                        | 24 ++++++++++++++++++
 ipv6ula/views.py                        | 33 ++++++++++++++++++++++---
 7 files changed, 90 insertions(+), 9 deletions(-)
 create mode 100644 ipv6ula/utils.py

diff --git a/ipv6ula/forms.py b/ipv6ula/forms.py
index 5be0447..0800a9f 100644
--- a/ipv6ula/forms.py
+++ b/ipv6ula/forms.py
@@ -12,3 +12,8 @@ class ULAForm(forms.ModelForm):
         validate_ula_prefix(prefix)
 
         return prefix
+
+class ULAGenerateForm(forms.ModelForm):
+    class Meta:
+        model = ULA
+        fields = [ 'name', 'organization', 'website' ]
diff --git a/ipv6ula/templates/ipv6ula/base.html b/ipv6ula/templates/ipv6ula/base.html
index d8870d4..8f50a7a 100644
--- a/ipv6ula/templates/ipv6ula/base.html
+++ b/ipv6ula/templates/ipv6ula/base.html
@@ -22,7 +22,10 @@
       <div class="collapse navbar-collapse"
            id="navbarSupportedContent">
         <ul class="navbar-nav mr-auto">
-          <li class="nav-item"> <a class="nav-link" href="/submit">Submit prefix</a></li>
+          <li class="nav-item"> <a class="nav-link"
+          href="/generate">Generate new prefix</a></li>
+          <li class="nav-item"> <a class="nav-link"
+          href="/submit">Submit existing prefix</a></li>
 
           {% if user.is_authenticated %}
           <span class="navbar-text">Logged in as {{ user }}.</span>
diff --git a/ipv6ula/templates/ipv6ula/ula_form.html b/ipv6ula/templates/ipv6ula/ula_form.html
index 20d6abd..b243123 100644
--- a/ipv6ula/templates/ipv6ula/ula_form.html
+++ b/ipv6ula/templates/ipv6ula/ula_form.html
@@ -5,16 +5,31 @@
 <div class="container">
   <div class="row">
     <div class="col">
+      <h1>
+      {% if method == 'submit' %}
+      <h1>Submitting existing prefix</h1>
+      <p>
+        You submit an existing prefix. Please follow the
+        <a href="https://tools.ietf.org/html/rfc4193">RFC4193</a>
+        rules for generation (basically: use a random network, do not
+        pick "cool numbers" as they will clash with somebody else in
+        the future).
+      </p>
+      {% elif method == 'generate' %}
+      <h1>Generate new prefix</h1>
+      <p>
+        A new random prefix will be generated for you.
+      </p>
+      {% endif %}
 
       <p>
         All ULA prefixes are /48 networks. Simply add the first IP address
         (without any netmask, for instance fd23:2323:2323::).
 
-        You can choose the name of your liking and an optional
-        organization name.
+        You can choose the name of your liking and an organization name.
       </p>
       <p>
-        ULA prefixes must be part of the fd00::/8 network.
+        ULA prefixes are always subnets of the fd00::/8 network.
       </p>
 
     </div>
diff --git a/ipv6ula/templates/ipv6ula/ula_list.html b/ipv6ula/templates/ipv6ula/ula_list.html
index 925256c..198ab41 100644
--- a/ipv6ula/templates/ipv6ula/ula_list.html
+++ b/ipv6ula/templates/ipv6ula/ula_list.html
@@ -34,7 +34,15 @@
       <a href="https://account.ungleich.ch">ungleich account</a>.
     </p>
   </div>
-
+  {% if messages %}
+  <div class="row">
+    {% for message in messages %}
+    <div class="alert alert-primary" role="alert">
+      {{ message }}
+    </div>
+    {% endfor %}
+  </div>
+  {% endif %}
   <div class="row">
     <table class="table table-striped">
       <thead>
diff --git a/ipv6ula/urls.py b/ipv6ula/urls.py
index 447d956..e814994 100644
--- a/ipv6ula/urls.py
+++ b/ipv6ula/urls.py
@@ -23,6 +23,7 @@ from ipv6ula import views
 urlpatterns = [
     path('', views.IndexView.as_view(), name='index'),
     path('submit/', views.SubmitView.as_view(), name='submit'),
+    path('generate/', views.GenerateView.as_view(), name='generate'),
     path('login/', views.LoginView.as_view(), name='login'),
     path('logout/', views.logout_view, name='logout'),
     path('admin/', admin.site.urls),
diff --git a/ipv6ula/utils.py b/ipv6ula/utils.py
new file mode 100644
index 0000000..6da38f1
--- /dev/null
+++ b/ipv6ula/utils.py
@@ -0,0 +1,24 @@
+import ipaddress
+import random
+
+def random_ula_net():
+    """
+
+    Use fd00::/8 as a basis
+    We have 40 bit of address space to then generate /48 networks
+    We generate a random integer between 0 and (2**40)-1
+    We then shift that number by 80 bits to fit into the correct position
+
+    Example:
+
+    >>> ula_net = ipaddress.IPv6Network("fd00::/8")
+    >>> ula_net[(2**40)-1 << 80]
+    IPv6Address('fdff:ffff:ffff::')
+    >>>
+
+    """
+    ula_net = ipaddress.IPv6Network("fd00::/8")
+    random_number = random.randrange(0, 2**40)
+    network = ula_net[random_number << 80]
+
+    return network
diff --git a/ipv6ula/views.py b/ipv6ula/views.py
index 2a01799..8e14454 100644
--- a/ipv6ula/views.py
+++ b/ipv6ula/views.py
@@ -2,6 +2,7 @@ from django.views.generic.list import ListView
 from django.views.generic.edit import CreateView
 from django.contrib.auth import views as auth_views
 from django.contrib.auth.mixins import LoginRequiredMixin
+from django.contrib.messages.views import SuccessMessageMixin
 
 from django.contrib.auth import logout
 from django.shortcuts import redirect
@@ -11,23 +12,47 @@ import ipaddress
 from django.conf import settings
 
 from .models import *
-from .forms import ULAForm
+from .forms import *
+from .utils import *
 
 class IndexView(ListView):
     model = ULA
     queryset = ULA.objects.order_by('prefix')
 
-class SubmitView(LoginRequiredMixin, CreateView):
+class GenerateSubmitView(LoginRequiredMixin, SuccessMessageMixin, CreateView):
     model = ULA
 
-    form_class = ULAForm
     login_url = '/login/'
     success_url = '/'
+    success_message = "%(the_prefix)s/48 was created successfully"
 
+    gen_method = "undef"
+
+    def get_success_message(self, cleaned_data):
+        return self.success_message % dict(cleaned_data,
+                                           the_prefix = self.object.prefix)
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        context['method'] = self.gen_method
+        return context
+
+class GenerateView(GenerateSubmitView):
+    form_class = ULAGenerateForm
+    gen_method = "generate"
 
     def form_valid(self, form):
         form.instance.owner = self.request.user
-        return super(SubmitView, self).form_valid(form)
+        form.instance.prefix = str(random_ula_net())
+        return super(GenerateView, self).form_valid(form)
+
+class SubmitView(GenerateSubmitView):
+    form_class = ULAForm
+    gen_method = "submit"
+
+    def form_valid(self, form):
+        form.instance.owner = self.request.user
+        return super().form_valid(form)
 
 class LoginView(auth_views.LoginView):
     template_name = 'ipv6ula/login.html'