Don't raise error when removing not existing IP address

When privileged delete_ip_address function is called to delete
IP address which is already not configured on device, it should
not fail with any error.

Change-Id: I9247ac899a76e5d9a2962d2cb81279f2d6f16c0b
Closes-Bug: #1757259

neutron/privileged/agent/linux/ip_lib.py

@@ -152,12 +152,21 @@ def add_ip_address(ip_version, ip, prefixlen, device, namespace, scope,
 @privileged.default.entrypoint
 def delete_ip_address(ip_version, ip, prefixlen, device, namespace):
     family = _IP_VERSION_FAMILY_MAP[ip_version]
-    _run_iproute_addr("delete",
-                      device,
-                      namespace,
-                      address=ip,
-                      mask=prefixlen,
-                      family=family)
+    try:
+        _run_iproute_addr("delete",
+                          device,
+                          namespace,
+                          address=ip,
+                          mask=prefixlen,
+                          family=family)
+    except NetlinkError as e:
+        # when trying to delete a non-existent IP address, pyroute2 raises
+        # NetlinkError with code EADDRNOTAVAIL (99, 'Cannot assign requested
+        # address')
+        # this shouldn't raise an error
+        if e.code == errno.EADDRNOTAVAIL:
+            return
+        raise
 
 
 @privileged.default.entrypoint

neutron/tests/functional/agent/linux/test_ip_lib.py

@@ -429,6 +429,10 @@ class IpLibTestCase(IpLibTestFramework):
         device_cidrs = [ip_info['cidr'] for ip_info in device.addr.list()]
         self.assertNotIn(cidr, device_cidrs)
 
+        # Try to delete not existing IP address, it should be just fine and
+        # finish without any error raised
+        device.addr.delete(cidr)
+
     def test_flush_ip_addresses(self):
         ip_addresses = [
             (netaddr.IPNetwork("10.10.10.10/30"), "global", '10.10.10.11'),