From ed11997bde84a952c40cda6c92af762712ee1627 Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Mon, 22 Apr 2024 11:00:04 +0200
Subject: [PATCH] Implement add_null_mx

---
 TODO                   |  2 ++
 example/example_org.py |  6 +++++-
 nsconfig/core.py       | 23 ++++++++++++++++++++---
 3 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/TODO b/TODO
index e1613f1..36631b1 100644
--- a/TODO
+++ b/TODO
@@ -4,3 +4,5 @@
 - DNSSEC
 - Automated generation of Null MX
 - Logging
+- Use dns.reversename.from_address?
+- Decouple min_ttl from default TTL
diff --git a/example/example_org.py b/example/example_org.py
index f3b49a4..02c5afe 100644
--- a/example/example_org.py
+++ b/example/example_org.py
@@ -1,6 +1,10 @@
 from example import nsc
 
-z = nsc.add_zone('example.org', daemon_options=['check-integrity yes;'])
+z = nsc.add_zone(
+    'example.org',
+    daemon_options=['check-integrity yes;'],
+    add_null_mx=True,
+)
 
 (z[""]
     .NS('ns1', 'ns2')
diff --git a/nsconfig/core.py b/nsconfig/core.py
index a5434ec..a091ffe 100644
--- a/nsconfig/core.py
+++ b/nsconfig/core.py
@@ -102,6 +102,7 @@ class NscZoneConfig:
     min_ttl: timedelta
     origin_server: str
     daemon_options: List[str]
+    add_null_mx: bool
 
     default_config: Optional['NscZoneConfig'] = None
 
@@ -114,6 +115,7 @@ class NscZoneConfig:
                  origin_server: Optional[str] = None,
                  daemon_options: Optional[List[str]] = None,
                  add_daemon_options: Optional[List[str]] = None,
+                 add_null_mx: Optional[bool] = None,
                  inherit_config: Optional['NscZoneConfig'] = None,
                  ) -> None:
         if inherit_config is None:
@@ -125,6 +127,7 @@ class NscZoneConfig:
         self.min_ttl = min_ttl if min_ttl is not None else inherit_config.min_ttl
         self.origin_server = origin_server if origin_server is not None else inherit_config.origin_server
         self.daemon_options = daemon_options if daemon_options is not None else inherit_config.daemon_options
+        self.add_null_mx = add_null_mx if add_null_mx is not None else inherit_config.add_null_mx
         if add_daemon_options is not None:
             self.daemon_options += add_daemon_options
 
@@ -144,6 +147,7 @@ NscZoneConfig.default_config = NscZoneConfig(
     min_ttl=timedelta(days=1),
     origin_server="",
     daemon_options=[],
+    add_null_mx=False,
 )
 
 
@@ -309,9 +313,10 @@ class NscZonePrimary(NscZone):
                     print(f'WARNING: Serial number overflow for zone {self.name}, current is {self.state.serial}')
 
     def process(self) -> None:
-        if self.zone_type == ZoneType.primary:
-            self.gen_hash()
-            self.gen_serial()
+        if self.config.add_null_mx:
+            self.gen_null_mx()
+        self.gen_hash()
+        self.gen_serial()
 
     def write_zone(self) -> None:
         self.update_soa()
@@ -347,6 +352,18 @@ class NscZonePrimary(NscZone):
 
         return self[subdomain]
 
+    def gen_null_mx(self) -> None:
+        for name, node in self.zone.items():
+            rds_a = node.get_rdataset(RdataClass.IN, RdataType.A)
+            rds_aaaa = node.get_rdataset(RdataClass.IN, RdataType.AAAA)
+            if rds_a or rds_aaaa:
+                mx_rds = node.get_rdataset(RdataClass.IN, RdataType.MX, create=True)
+                if not mx_rds:
+                    mx_rds.add(
+                        dns.rdtypes.ANY.MX.MX(RdataClass.IN, RdataType.MX, 0, dns.name.root),
+                        ttl=self._min_ttl,
+                    )
+
 
 class NscZoneSecondary(NscZone):
     primary_server: IPAddress
-- 
2.39.2