net: support reading ipv6 dhcp config from initramfs

This adds support for understanding 'dhcp6' as a protocol
that can be written into /run/net-IFACE.cfg files by the initramfs.

The end result is supporting ipv6 dhcp from initramfs boot
all the way into iscsi root.

LP: #1621615, #1621507

2 files changed, 53 insertions, 5 deletions

diff --git a/cloudinit/net/cmdline.py b/cloudinit/net/cmdline.py
index 822a020b..933317d5 100644
--- a/cloudinit/net/cmdline.py
+++ b/cloudinit/net/cmdline.py
@@ -66,7 +66,9 @@ def _klibc_to_config_entry(content, mac_addrs=None):
     provided here.  There is no good documentation on this unfortunately.
 
     DEVICE=<name> is expected/required and PROTO should indicate if
-    this is 'static' or 'dhcp'.
+    this is 'static' or 'dhcp' or 'dhcp6' (LP: #1621507).
+    note that IPV6PROTO is also written by newer code to address the
+    possibility of both ipv4 and ipv6 getting addresses.
     """
 
     if mac_addrs is None:
@@ -86,7 +88,7 @@ def _klibc_to_config_entry(content, mac_addrs=None):
         else:
             proto = 'static'
 
-    if proto not in ('static', 'dhcp'):
+    if proto not in ('static', 'dhcp', 'dhcp6'):
         raise ValueError("Unexpected value for PROTO: %s" % proto)
 
     iface = {
@@ -98,12 +100,15 @@ def _klibc_to_config_entry(content, mac_addrs=None):
     if name in mac_addrs:
         iface['mac_address'] = mac_addrs[name]
 
-    # originally believed there might be IPV6* values
-    for v, pre in (('ipv4', 'IPV4'),):
+    # Handle both IPv4 and IPv6 values
+    for v, pre in (('ipv4', 'IPV4'), ('ipv6', 'IPV6')):
         # if no IPV4ADDR or IPV6ADDR, then go on.
         if pre + "ADDR" not in data:
             continue
-        subnet = {'type': proto, 'control': 'manual'}
+
+        # PROTO for ipv4, IPV6PROTO for ipv6
+        cur_proto = data.get(pre + 'PROTO', proto)
+        subnet = {'type': cur_proto, 'control': 'manual'}
 
         # these fields go right on the subnet
         for key in ('NETMASK', 'BROADCAST', 'GATEWAY'):
diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 41b9a6d0..78c080ca 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -53,6 +53,45 @@ DHCP_EXPECTED_1 = {
                  'dns_nameservers': ['192.168.122.1']}],
 }
 
+DHCP6_CONTENT_1 = """
+DEVICE=eno1
+HOSTNAME=
+DNSDOMAIN=
+reason='PREINIT'
+interface='eno1'
+DEVICE=eno1
+HOSTNAME=
+DNSDOMAIN=
+reason='FAIL'
+interface='eno1'
+DEVICE=eno1
+HOSTNAME=
+DNSDOMAIN=
+reason='PREINIT6'
+interface='eno1'
+DEVICE=eno1
+IPV6PROTO=dhcp6
+IPV6ADDR=2001:67c:1562:8010:0:1::
+IPV6NETMASK=64
+IPV6DNS0=2001:67c:1562:8010::2:1
+IPV6DOMAINSEARCH=
+HOSTNAME=
+DNSDOMAIN=
+reason='BOUND6'
+interface='eno1'
+new_ip6_address='2001:67c:1562:8010:0:1::'
+new_ip6_prefixlen='64'
+new_dhcp6_name_servers='2001:67c:1562:8010::2:1'
+"""
+
+DHCP6_EXPECTED_1 = {
+    'name': 'eno1',
+    'type': 'physical',
+    'subnets': [{'control': 'manual',
+                 'dns_nameservers': ['2001:67c:1562:8010::2:1'],
+                 'netmask': '64',
+                 'type': 'dhcp6'}]}
+
 
 STATIC_CONTENT_1 = """
 DEVICE='eth1'
@@ -590,6 +629,10 @@ class TestCmdlineConfigParsing(TestCase):
         found = cmdline._klibc_to_config_entry(DHCP_CONTENT_1)
         self.assertEqual(found, ('eth0', DHCP_EXPECTED_1))
 
+    def test_cmdline_convert_dhcp6(self):
+        found = cmdline._klibc_to_config_entry(DHCP6_CONTENT_1)
+        self.assertEqual(found, ('eno1', DHCP6_EXPECTED_1))
+
     def test_cmdline_convert_static(self):
         found = cmdline._klibc_to_config_entry(STATIC_CONTENT_1)
         self.assertEqual(found, ('eth1', STATIC_EXPECTED_1))