Adding netmask to dnsmasq argument --dhcp-range

By default, dnsmasq will try to guess the proper subnet size but
sometimes it will fail. This patch provides the network netmask
to dnsmasq via the --dhcp-range argument.

Fixes: bug #1154929

Change-Id: I74d62c837b5310004b9151851697e3ea3b475f92
(cherry picked from commit fb151b5)

nova/network/linux_net.py

@@ -1019,9 +1019,10 @@ def restart_dhcp(context, dev, network_ref):
            '--pid-file=%s' % _dhcp_file(dev, 'pid'),
            '--listen-address=%s' % network_ref['dhcp_server'],
            '--except-interface=lo',
-           '--dhcp-range=set:%s,%s,static,%ss' %
+           '--dhcp-range=set:%s,%s,static,%s,%ss' %
                          (network_ref['label'],
                           network_ref['dhcp_start'],
+                          network_ref['netmask'],
                           CONF.dhcp_lease_time),
            '--dhcp-lease-max=%s' % len(netaddr.IPNetwork(network_ref['cidr'])),
            '--dhcp-hostsfile=%s' % _dhcp_file(dev, 'conf'),

nova/tests/network/test_linux_net.py

@@ -480,6 +480,7 @@ def _test_dnsmasq_execute(self, extra_expected=None):
                        'label': 'fake',
                        'multi_host': False,
                        'cidr': '10.0.0.0/24',
+                       'netmask': '255.255.255.0',
                        'dns1': '8.8.4.4',
                        'dhcp_start': '1.0.0.2',
                        'dhcp_server': '10.0.0.1'}
@@ -507,8 +508,9 @@ def fake_execute(*args, **kwargs):
           '--pid-file=%s' % linux_net._dhcp_file(dev, 'pid'),
           '--listen-address=%s' % network_ref['dhcp_server'],
           '--except-interface=lo',
-          "--dhcp-range=set:%s,%s,static,%ss" % (network_ref['label'],
+          "--dhcp-range=set:%s,%s,static,%s,%ss" % (network_ref['label'],
                                                    network_ref['dhcp_start'],
+                                                   network_ref['netmask'],
                                                    CONF.dhcp_lease_time),
           '--dhcp-lease-max=256',
           '--dhcp-hostsfile=%s' % linux_net._dhcp_file(dev, 'conf'),