From 8447fa0db941b6d582ca40f2e8dd3081887ba1cb Mon Sep 17 00:00:00 2001
From: Otthorn <otthorn@crans.org>
Date: Wed, 14 Apr 2021 19:16:06 +0200
Subject: [PATCH] Update serial number correctly

---
 lib.py | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/lib.py b/lib.py
index 7f6f5af..a2ed53e 100644
--- a/lib.py
+++ b/lib.py
@@ -82,6 +82,17 @@ def get_serial(dns_zone):
 
     return serial
 
+def update_serial(serial, serial_bits=32):
+    """Update serial number
+
+    According to RFC 1982 and Knot implementation.
+    SERIAL_BITS = 32 by default.
+    """
+
+    serial = serial + 1 % 2**32
+
+    return serial
+
 def soa_handler(re2o_zone, dns_zone):
     """Handler for SOA record"""
 
@@ -93,6 +104,7 @@ def soa_handler(re2o_zone, dns_zone):
     
     origin = dns_zone.origin
     serial = get_serial(origin)
+    serial = update_serial(serial)
     logging.debug(f"[SOA] zone_origin={origin} serial={serial}")
 
     soa_obj = SOA.SOA(