Merge ~cgrabowski/maas:fix_overflowing_subnet_overlap into maas:master

[Christian Grabowski]

pass correct excludable subnets into rfc2317 glue config

add overlap test for overflowing IP

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10145/console
COMMIT: 02b050a7c57d1d0b644bf8472ca846a0842e83c1

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10146/console
COMMIT: 5459402edae112d1993881a61691e32e186d49ea

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 428b7caf56aa117a5b0d3c7b787a4d2ca3758c02

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10155/console
COMMIT: 1b039c7d52f68a678a0c497f6781056ba93d07dc

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10156/console
COMMIT: 6d17aac2dced9d8322cff86459855edd903e7347

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 2efaf1b09f93a3d99be7b39b3f714ad2df8d5e27

review: Approve

[Björn Tillenius (bjornt)]

Thanks for the fix! I added some comments, but feel free to merge after you've addressed them.

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10158/console
COMMIT: c4aaa3de8e50dffa6c0aa3a76a22d71acdeb8cb7

review: Needs Fixing

[MAAS Lander (maas-lander)]

UNIT TESTS
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 0159486fc34991adb070790391362241115ecae8

review: Approve

[MAAS Lander (maas-lander)]

LANDING
-b fix_overflowing_subnet_overlap lp:~cgrabowski/maas/+git/maas into -b master lp:~maas-committers/maas

STATUS: FAILED BUILD
LOG: http://maas-ci.internal:8080/job/maas/job/branch-tester/10160/consoleText

diff --git a/src/maasserver/dns/tests/test_zonegenerator.py b/src/maasserver/dns/tests/test_zonegenerator.py
index 780e3d1..0d96159 100644
--- a/src/maasserver/dns/tests/test_zonegenerator.py
+++ b/src/maasserver/dns/tests/test_zonegenerator.py
@@ -366,6 +366,31 @@ class TestZoneGenerator(MAASServerTestCase):
             ),
         )
 
+    def test_yields_forward_and_reverse_zone_no_overlap_bug(self):
+        domain = factory.make_Domain(name="overlap")
+        subnet1 = factory.make_Subnet(cidr="192.168.33.0/25")
+        subnet2 = factory.make_Subnet(cidr="192.168.35.0/26")
+        subnet3 = factory.make_Subnet(cidr="192.168.36.0/26")
+        zones = ZoneGenerator(
+            domain,
+            [
+                subnet2,
+                subnet1,
+                subnet3,
+            ],  # purposely out of order to assert subnets are being sorted
+            serial=random.randint(0, 65535),
+        ).as_list()
+        expected_domains = [
+            "0-25.33.168.192.in-addr.arpa",
+            "0-26.35.168.192.in-addr.arpa",
+            "0-26.36.168.192.in-addr.arpa",
+            "overlap",
+        ]
+        zone_names = [
+            info.zone_name for zone in zones for info in zone.zone_info
+        ]
+        self.assertCountEqual(zone_names, expected_domains)
+
     def test_yields_forward_and_reverse_zone_no_overlap(self):
         domain = factory.make_Domain(name="overlap")
         vlan1 = factory.make_VLAN(vid=1, dhcp_on=True)
@@ -389,33 +414,25 @@ class TestZoneGenerator(MAASServerTestCase):
             serial=random.randint(0, 65535),
         ).as_list()
         self.assertEqual(len(zones), 7)
-        expected_domains = set(
-            [
-                "overlap",
-                "36.232.10.in-addr.arpa",
-                "32.232.10.in-addr.arpa",
-                "6.232.10.in-addr.arpa",
-                "36.2.10.in-addr.arpa",
-                "36.231.10.in-addr.arpa",
-                "40.232.10.in-addr.arpa",
-                "38.232.10.in-addr.arpa",
-                "34.232.10.in-addr.arpa",
-                "35.232.10.in-addr.arpa",
-                "39.232.10.in-addr.arpa",
-                "37.232.10.in-addr.arpa",
-                "33.232.10.in-addr.arpa",
-            ]
-        )
-        zone_names = set(
+        expected_domains = [
+            "overlap",
+            "36.232.10.in-addr.arpa",
+            "32.232.10.in-addr.arpa",
+            "6.232.10.in-addr.arpa",
+            "36.2.10.in-addr.arpa",
+            "36.231.10.in-addr.arpa",
+            "40.232.10.in-addr.arpa",
+            "38.232.10.in-addr.arpa",
+            "34.232.10.in-addr.arpa",
+            "35.232.10.in-addr.arpa",
+            "39.232.10.in-addr.arpa",
+            "37.232.10.in-addr.arpa",
+            "33.232.10.in-addr.arpa",
+        ]
+        zone_names = [
             info.zone_name for zone in zones for info in zone.zone_info
-        )
-        self.assertEqual(zone_names, expected_domains)
-        for expected_domain in expected_domains:
-            self.assertIn(
-                expected_domain,
-                zone_names,
-                f"{expected_domain} is not in domains",
-            )
+        ]
+        self.assertCountEqual(zone_names, expected_domains)
 
     def test_with_node_yields_fwd_and_rev_zone(self):
         default_domain = Domain.objects.get_default_domain().name
diff --git a/src/maasserver/dns/zonegenerator.py b/src/maasserver/dns/zonegenerator.py
index 0d798ac..bd6401a 100644
--- a/src/maasserver/dns/zonegenerator.py
+++ b/src/maasserver/dns/zonegenerator.py
@@ -441,9 +441,7 @@ class ZoneGenerator:
                 network=network,
                 ns_host_name=ns_host_name,
                 rfc2317_ranges=ranges,
-                exclude=set(
-                    [IPNetwork(s.cidr) for s in subnets if s is not subnet]
-                ),
+                exclude=set([IPNetwork(s.cidr) for s in subnets]),
             )
 
     def __iter__(self):
diff --git a/src/provisioningserver/dns/zoneconfig.py b/src/provisioningserver/dns/zoneconfig.py
index 50ef9dc..c88a9ba 100644
--- a/src/provisioningserver/dns/zoneconfig.py
+++ b/src/provisioningserver/dns/zoneconfig.py
@@ -408,6 +408,10 @@ class DNSReverseZoneConfig(DomainConfigBase):
                     try:
                         base += 1
                         first += step
+                        if (
+                            first > last
+                        ):  # if the excluding subnet pushes the base IP beyond the bounds of the generating subnet, we've reached the end and return early
+                            return info
                         continue
                     except IndexError:
                         # IndexError occurs when we go from 255.255.255.255 to