ipaddr: Handle network address in ipmath (#57149)

* Updated testcase, documentation

Fixes: #54457

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

docs/docsite/rst/user_guide/playbooks_filters_ipaddr.rst

@@ -448,6 +448,15 @@ Here are a few simple examples::
     # {{ '192.168.0.5' | ipmath(-10) }}
     192.167.255.251
 
+    # {{ '192.168.1.1/24' | ipmath(5) }}
+    192.168.1.6
+
+    # {{ '192.168.1.6/24' | ipmath(-5) }}
+    192.168.1.1
+
+    # {{ '192.168.2.6/24' | ipmath(-10) }}
+    192.168.1.252
+
     # {{ '2001::1' | ipmath(10) }}
     2001::b
 

lib/ansible/plugins/filter/ipaddr.py

@@ -673,8 +673,11 @@ def ipaddr(value, query='', version=False, alias='ipaddr'):
 
 def ipmath(value, amount):
     try:
-        ip = netaddr.IPAddress(value)
-    except netaddr.AddrFormatError:
+        if '/' in value:
+            ip = netaddr.IPNetwork(value).ip
+        else:
+            ip = netaddr.IPAddress(value)
+    except (netaddr.AddrFormatError, ValueError):
         msg = 'You must pass a valid IP address; {0} is invalid'.format(value)
         raise errors.AnsibleFilterError(msg)
 

test/units/plugins/filter/test_ipaddr.py

@@ -481,6 +481,10 @@ class TestIpFilter(unittest.TestCase):
         self.assertEqual(ipmath('192.168.1.5', -5), '192.168.1.0')
         self.assertEqual(ipmath('192.168.0.5', -10), '192.167.255.251')
 
+        self.assertEqual(ipmath('192.168.1.1/24', 5), '192.168.1.6')
+        self.assertEqual(ipmath('192.168.1.6/24', -5), '192.168.1.1')
+        self.assertEqual(ipmath('192.168.2.6/24', -10), '192.168.1.252')
+
         self.assertEqual(ipmath('2001::1', 8), '2001::9')
         self.assertEqual(ipmath('2001::1', 9), '2001::a')
         self.assertEqual(ipmath('2001::1', 10), '2001::b')