net: IPv6, accept_ra, slaac, stateless (#51)

Router advertisements are required for the default route
to be set up, thus accept_ra should be enabled for
dhcpv6-stateful.

sysconf: IPV6_FORCE_ACCEPT_RA controls accept_ra sysctl.
eni: mode static and mode dhcp 'accept_ra' controls sysctl.

Add 'accept-ra: true|false' parameter to config v1 and
v2. When True: accept_ra is set to '1'. When False:
accept_ra is set to '0'. When not defined in config the
value is left to the operating system default.

This change also extend the IPv6 support to distinguish
between slaac and dhcpv6-stateless. SLAAC is autoconfig
without any options from DHCP, while stateless auto-configures
the address and the uses DHCP for other options.

LP: #1806014
LP: #1808647

1 files changed, 7 insertions, 2 deletions

diff --git a/cloudinit/net/netplan.py b/cloudinit/net/netplan.py
index 749d46f8..14d3999f 100644
--- a/cloudinit/net/netplan.py
+++ b/cloudinit/net/netplan.py
@@ -4,7 +4,7 @@ import copy
 import os
 
 from . import renderer
-from .network_state import subnet_is_ipv6, NET_CONFIG_TO_V2
+from .network_state import subnet_is_ipv6, NET_CONFIG_TO_V2, IPV6_DYNAMIC_TYPES
 
 from cloudinit import log as logging
 from cloudinit import util
@@ -52,7 +52,8 @@ def _extract_addresses(config, entry, ifname, features=None):
          'mtu': 1480,
          'netmask': 64,
          'type': 'static'}],
-      'type: physical'
+      'type: physical',
+      'accept-ra': 'true'
     }
 
     An entry dictionary looks like:
@@ -95,6 +96,8 @@ def _extract_addresses(config, entry, ifname, features=None):
             if sn_type == 'dhcp':
                 sn_type += '4'
             entry.update({sn_type: True})
+        elif sn_type in IPV6_DYNAMIC_TYPES:
+            entry.update({'dhcp6': True})
         elif sn_type in ['static']:
             addr = "%s" % subnet.get('address')
             if 'prefix' in subnet:
@@ -147,6 +150,8 @@ def _extract_addresses(config, entry, ifname, features=None):
         ns = entry.get('nameservers', {})
         ns.update({'search': searchdomains})
         entry.update({'nameservers': ns})
+    if 'accept-ra' in config and config['accept-ra'] is not None:
+        entry.update({'accept-ra': util.is_true(config.get('accept-ra'))})
 
 
 def _extract_bond_slaves_by_name(interfaces, entry, bond_master):