Better default for my_ip if 8.8.8.8 is unreachable

Run if route/show, extract ipv4 addresses and pick the first one.
Fall back to 127.0.0.1 as before if we don't find anything
or if we have running the ip route/show commands

Fixes LP# 1193013

Change-Id: If73f0f6bf67f858f7506220debab0f74cc9e3cb4

nova/netconf.py

@@ -21,6 +21,8 @@
 
 from oslo.config import cfg
 
+from nova import utils
+
 CONF = cfg.CONF
 
 
@@ -40,7 +42,7 @@ def _get_my_ip():
         csock.close()
         return addr
     except socket.error:
-        return "127.0.0.1"
+        return utils.get_my_ipv4_address()
 
 
 netconf_opts = [

nova/tests/test_utils.py

@@ -193,6 +193,92 @@ def test_accepts_dictionaries(self):
         self.assertEquals(['b_1'], f(input, "a/b"))
 
 
+class GetMyIP4AddressTestCase(test.TestCase):
+    def test_get_my_ipv4_address_with_no_ipv4(self):
+        response = """172.16.0.0/16 via 172.16.251.13 dev tun1
+172.16.251.1 via 172.16.251.13 dev tun1
+172.16.251.13 dev tun1  proto kernel  scope link  src 172.16.251.14
+172.24.0.0/16 via 172.16.251.13 dev tun1
+192.168.122.0/24 dev virbr0  proto kernel  scope link  src 192.168.122.1"""
+
+        def fake_execute(*args, **kwargs):
+            return response, None
+
+        self.stubs.Set(utils, 'execute', fake_execute)
+        address = utils.get_my_ipv4_address()
+        self.assertEqual(address, '127.0.0.1')
+
+    def test_get_my_ipv4_address_bad_process(self):
+        def fake_execute(*args, **kwargs):
+            raise processutils.ProcessExecutionError()
+
+        self.stubs.Set(utils, 'execute', fake_execute)
+        address = utils.get_my_ipv4_address()
+        self.assertEqual(address, '127.0.0.1')
+
+    def test_get_my_ipv4_address_with_single_interface(self):
+        response_route = """default via 192.168.1.1 dev wlan0  proto static
+192.168.1.0/24 dev wlan0  proto kernel  scope link  src 192.168.1.137  metric 9
+"""
+        response_addr = """
+1: lo    inet 127.0.0.1/8 scope host lo
+3: wlan0    inet 192.168.1.137/24 brd 192.168.1.255 scope global wlan0
+"""
+
+        def fake_execute(*args, **kwargs):
+            if 'route' in args:
+                return response_route, None
+            return response_addr, None
+
+        self.stubs.Set(utils, 'execute', fake_execute)
+        address = utils.get_my_ipv4_address()
+        self.assertEqual(address, '192.168.1.137')
+
+    def test_get_my_ipv4_address_with_multi_ipv4_on_single_interface(self):
+        response_route = """
+172.18.56.0/24 dev customer  proto kernel  scope link  src 172.18.56.22
+169.254.0.0/16 dev customer  scope link  metric 1031
+default via 172.18.56.1 dev customer
+"""
+        response_addr = (""
+"31: customer    inet 172.18.56.22/24 brd 172.18.56.255 scope global"
+" customer\n"
+"31: customer    inet 172.18.56.32/24 brd 172.18.56.255 scope global "
+"secondary customer")
+
+        def fake_execute(*args, **kwargs):
+            if 'route' in args:
+                return response_route, None
+            return response_addr, None
+
+        self.stubs.Set(utils, 'execute', fake_execute)
+        address = utils.get_my_ipv4_address()
+        self.assertEqual(address, '172.18.56.22')
+
+    def test_get_my_ipv4_address_with_multiple_interfaces(self):
+        response_route = """
+169.1.9.0/24 dev eth1  proto kernel  scope link  src 169.1.9.10
+172.17.248.0/21 dev eth0  proto kernel  scope link  src 172.17.255.9
+169.254.0.0/16 dev eth0  scope link  metric 1002
+169.254.0.0/16 dev eth1  scope link  metric 1003
+default via 172.17.248.1 dev eth0  proto static
+"""
+        response_addr = """
+1: lo    inet 127.0.0.1/8 scope host lo
+2: eth0    inet 172.17.255.9/21 brd 172.17.255.255 scope global eth0
+3: eth1    inet 169.1.9.10/24 scope global eth1
+"""
+
+        def fake_execute(*args, **kwargs):
+            if 'route' in args:
+                return response_route, None
+            return response_addr, None
+
+        self.stubs.Set(utils, 'execute', fake_execute)
+        address = utils.get_my_ipv4_address()
+        self.assertEqual(address, '172.17.255.9')
+
+
 class GenericUtilsTestCase(test.TestCase):
     def test_parse_server_string(self):
         result = utils.parse_server_string('::1')

nova/utils.py

@@ -321,6 +321,62 @@ def last_octet(address):
     return int(address.split('.')[-1])
 
 
+def get_my_ipv4_address():
+    """Run ip route/addr commands to figure out the best ipv4
+    """
+    LOCALHOST = '127.0.0.1'
+    try:
+        out = execute('ip', '-f', 'inet', '-o', 'route', 'show',
+                      run_as_root=True)
+
+        # Find the default route
+        regex_default = ('default\s*via\s*'
+                         '(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})'
+                         '\s*dev\s*(\w*)\s*')
+        default_routes = re.findall(regex_default, out[0])
+        if not default_routes:
+            return LOCALHOST
+        gateway, iface = default_routes[0]
+
+        # Find the right subnet for the gateway/interface for
+        # the default route
+        route = ('(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\/(\d{1,2})'
+              '\s*dev\s*(\w*)\s*')
+        for match in re.finditer(route, out[0]):
+            subnet = netaddr.IPNetwork(match.group(1) + "/" + match.group(2))
+            if (match.group(3) == iface and
+                netaddr.IPAddress(gateway) in subnet):
+                try:
+                    return _get_ipv4_address_for_interface(iface)
+                except exception.NovaException:
+                    pass
+    except Exception as ex:
+        LOG.error(_("Couldn't get IPv4 : %(ex)s") % {'ex': ex})
+    return LOCALHOST
+
+
+def _get_ipv4_address_for_interface(iface):
+    """Run ip addr show for an interface and grab its ipv4 addresses
+    """
+    try:
+        out = execute('ip', '-f', 'inet', '-o', 'addr', 'show', iface,
+                      run_as_root=True)
+        regexp_address = re.compile('inet\s*'
+                                    '(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})')
+        address = [m.group(1) for m in regexp_address.finditer(out[0])
+                   if m.group(1) != '127.0.0.1']
+        if address:
+            return address[0]
+        else:
+            msg = _('IPv4 address is not found.: %s') % out[0]
+            raise exception.NovaException(msg)
+    except Exception as ex:
+        msg = _("Couldn't get IPv4 of %(interface)s"
+                " : %(ex)s") % {'interface': iface, 'ex': ex}
+        LOG.error(msg)
+        raise exception.NovaException(msg)
+
+
 def get_my_linklocal(interface):
     try:
         if_str = execute('ip', '-f', 'inet6', '-o', 'addr', 'show', interface)