Revert "revert drop ixlan changes (#21) (#631)" (#640)

This reverts commit 676f850bfe.

peeringdb_server/admin.py

@@ -10,7 +10,7 @@ import django.urls
 from django.conf.urls import url
 from django.shortcuts import redirect, Http404
 from django.contrib.contenttypes.models import ContentType
-from django.contrib import admin
+from django.contrib import admin, messages
 from django.contrib.auth import forms
 from django.contrib.admin import helpers
 from django.contrib.admin.actions import delete_selected
@@ -296,6 +296,15 @@ def soft_delete(modeladmin, request, queryset):
     if request.user:
         reversion.set_user(request.user)
 
+    if queryset.model.handleref.tag == "ixlan":
+        messages.error(
+            request,
+            _(
+                "Ixlans can no longer be directly deleted as they are now synced to the parent exchange"
+            ),
+        )
+        return
+
     for row in queryset:
         row.delete()
 
@@ -406,7 +415,13 @@ class IXLanInline(SanitizedAdmin, admin.StackedInline):
     extra = 0
     form = StatusForm
     exclude = ["arp_sponge"]
-    readonly_fields = ["ixf_import_attempt_info", "prefixes"]
+    readonly_fields = ["id", "ixf_import_attempt_info", "prefixes"]
+
+    def has_add_permission(self, request):
+        return False
+
+    def has_delete_permission(self, request, obj):
+        return False
 
     def ixf_import_attempt_info(self, obj):
         if obj.ixf_import_attempt:
@@ -553,6 +568,7 @@ class IXLanAdminForm(StatusForm):
 
 
 class IXLanAdmin(SoftDeleteAdmin):
+    actions = []
     list_display = ("ix", "name", "descr", "status")
     search_fields = ("name", "ix__name")
     list_filter = (StatusFilter,)