dhcp: Support RedHat dhcp rfc3442 lease format for option 121 (#76)

RedHat dhcp client writes out rfc3442 classless-static-routes in a different format[1]
than what is found in isc-dhcp clients.  This patch adds support for the RedHat format.

1. Background details on the format
 https://bugzilla.redhat.com/show_bug.cgi?id=516325
 https://github.com/vaijab/fedora-dhcp/blob/e83fb19c51765442d77fa60596bfdb2b3b9fbe2e/dhcp-rfc3442-classless-static-routes.patch#L252 
 https://github.com/heftig/NetworkManager/blob/f56c82d86122fc45304fc829b5f1e4766ed51589/src/dhcp-manager/nm-dhcp-client.c#L978

LP: #1850642

1 files changed, 65 insertions, 0 deletions

diff --git a/cloudinit/net/tests/test_dhcp.py b/cloudinit/net/tests/test_dhcp.py
index 91f503c9..c3fa1e04 100644
--- a/cloudinit/net/tests/test_dhcp.py
+++ b/cloudinit/net/tests/test_dhcp.py
@@ -90,6 +90,32 @@ class TestDHCPRFC3442(CiTestCase):
         write_file(lease_file, content)
         self.assertItemsEqual(expected, parse_dhcp_lease_file(lease_file))
 
+    def test_parse_lease_finds_classless_static_routes(self):
+        """
+        parse_dhcp_lease_file returns classless-static-routes
+        for Centos lease format.
+        """
+        lease_file = self.tmp_path('leases')
+        content = dedent("""
+            lease {
+              interface "wlp3s0";
+              fixed-address 192.168.2.74;
+              option subnet-mask 255.255.255.0;
+              option routers 192.168.2.1;
+              option classless-static-routes 0 130.56.240.1;
+              renew 4 2017/07/27 18:02:30;
+              expire 5 2017/07/28 07:08:15;
+            }
+        """)
+        expected = [
+            {'interface': 'wlp3s0', 'fixed-address': '192.168.2.74',
+             'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1',
+             'classless-static-routes': '0 130.56.240.1',
+             'renew': '4 2017/07/27 18:02:30',
+             'expire': '5 2017/07/28 07:08:15'}]
+        write_file(lease_file, content)
+        self.assertItemsEqual(expected, parse_dhcp_lease_file(lease_file))
+
     @mock.patch('cloudinit.net.dhcp.EphemeralIPv4Network')
     @mock.patch('cloudinit.net.dhcp.maybe_perform_dhcp_discovery')
     def test_obtain_lease_parses_static_routes(self, m_maybe, m_ipv4):
@@ -112,6 +138,31 @@ class TestDHCPRFC3442(CiTestCase):
             'router': '192.168.2.1'}
         m_ipv4.assert_called_with(**expected_kwargs)
 
+    @mock.patch('cloudinit.net.dhcp.EphemeralIPv4Network')
+    @mock.patch('cloudinit.net.dhcp.maybe_perform_dhcp_discovery')
+    def test_obtain_centos_lease_parses_static_routes(self, m_maybe, m_ipv4):
+        """
+        EphemeralDHPCv4 parses rfc3442 routes for EphemeralIPv4Network
+        for Centos Lease format
+        """
+        lease = [
+            {'interface': 'wlp3s0', 'fixed-address': '192.168.2.74',
+             'subnet-mask': '255.255.255.0', 'routers': '192.168.2.1',
+             'classless-static-routes': '0 130.56.240.1',
+             'renew': '4 2017/07/27 18:02:30',
+             'expire': '5 2017/07/28 07:08:15'}]
+        m_maybe.return_value = lease
+        eph = net.dhcp.EphemeralDHCPv4()
+        eph.obtain_lease()
+        expected_kwargs = {
+            'interface': 'wlp3s0',
+            'ip': '192.168.2.74',
+            'prefix_or_mask': '255.255.255.0',
+            'broadcast': '192.168.2.255',
+            'static_routes': [('0.0.0.0/0', '130.56.240.1')],
+            'router': '192.168.2.1'}
+        m_ipv4.assert_called_with(**expected_kwargs)
+
 
 class TestDHCPParseStaticRoutes(CiTestCase):
 
@@ -181,6 +232,20 @@ class TestDHCPParseStaticRoutes(CiTestCase):
         logs = self.logs.getvalue()
         self.assertIn(rfc3442, logs.splitlines()[0])
 
+    def test_redhat_format(self):
+        redhat_format = "24.191.168.128 192.168.128.1,0 192.168.128.1"
+        self.assertEqual(sorted([
+            ("191.168.128.0/24", "192.168.128.1"),
+            ("0.0.0.0/0", "192.168.128.1")
+        ]), sorted(parse_static_routes(redhat_format)))
+
+    def test_redhat_format_with_a_space_too_much_after_comma(self):
+        redhat_format = "24.191.168.128 192.168.128.1, 0 192.168.128.1"
+        self.assertEqual(sorted([
+            ("191.168.128.0/24", "192.168.128.1"),
+            ("0.0.0.0/0", "192.168.128.1")
+        ]), sorted(parse_static_routes(redhat_format)))
+
 
 class TestDHCPDiscoveryClean(CiTestCase):
     with_logs = True