From fa47d527a03a00319936323f0a857fbecafceaf7 Mon Sep 17 00:00:00 2001
From: Ryan Harper <ryan.harper@canonical.com>
Date: Mon, 9 Sep 2019 21:13:01 +0000
Subject: net,Oracle: Add support for netfailover detection

Add support for detecting netfailover[1] device 3-tuple in networking
layer.  In the Oracle datasource ensure that if a provided network
config, either fallback or provided config includes a netfailover master
to remove any MAC address value as this can break under 3-netdev
as the other two devices have the same MAC.

1. https://www.kernel.org/doc/html/latest/networking/net_failover.html
---
 cloudinit/sources/DataSourceOracle.py | 62 ++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

(limited to 'cloudinit/sources/DataSourceOracle.py')

diff --git a/cloudinit/sources/DataSourceOracle.py b/cloudinit/sources/DataSourceOracle.py
index 1cb0636c..eec87403 100644
--- a/cloudinit/sources/DataSourceOracle.py
+++ b/cloudinit/sources/DataSourceOracle.py
@@ -16,7 +16,7 @@ Notes:
 """
 
 from cloudinit.url_helper import combine_url, readurl, UrlError
-from cloudinit.net import dhcp, get_interfaces_by_mac
+from cloudinit.net import dhcp, get_interfaces_by_mac, is_netfail_master
 from cloudinit import net
 from cloudinit import sources
 from cloudinit import util
@@ -108,6 +108,56 @@ def _add_network_config_from_opc_imds(network_config):
                 'match': {'macaddress': mac_address}}
 
 
+def _ensure_netfailover_safe(network_config):
+    """
+    Search network config physical interfaces to see if any of them are
+    a netfailover master.  If found, we prevent matching by MAC as the other
+    failover devices have the same MAC but need to be ignored.
+
+    Note: we rely on cloudinit.net changes which prevent netfailover devices
+    from being present in the provided network config.  For more details about
+    netfailover devices, refer to cloudinit.net module.
+
+    :param network_config
+       A v1 or v2 network config dict with the primary NIC, and possibly
+       secondary nic configured.  This dict will be mutated.
+
+    """
+    # ignore anything that's not an actual network-config
+    if 'version' not in network_config:
+        return
+
+    if network_config['version'] not in [1, 2]:
+        LOG.debug('Ignoring unknown network config version: %s',
+                  network_config['version'])
+        return
+
+    mac_to_name = get_interfaces_by_mac()
+    if network_config['version'] == 1:
+        for cfg in [c for c in network_config['config'] if 'type' in c]:
+            if cfg['type'] == 'physical':
+                if 'mac_address' in cfg:
+                    mac = cfg['mac_address']
+                    cur_name = mac_to_name.get(mac)
+                    if not cur_name:
+                        continue
+                    elif is_netfail_master(cur_name):
+                        del cfg['mac_address']
+
+    elif network_config['version'] == 2:
+        for _, cfg in network_config.get('ethernets', {}).items():
+            if 'match' in cfg:
+                macaddr = cfg.get('match', {}).get('macaddress')
+                if macaddr:
+                    cur_name = mac_to_name.get(macaddr)
+                    if not cur_name:
+                        continue
+                    elif is_netfail_master(cur_name):
+                        del cfg['match']['macaddress']
+                        del cfg['set-name']
+                        cfg['match']['name'] = cur_name
+
+
 class DataSourceOracle(sources.DataSource):
 
     dsname = 'Oracle'
@@ -208,9 +258,13 @@ class DataSourceOracle(sources.DataSource):
         We nonetheless return cmdline provided config if present
         and fallback to generate fallback."""
         if self._network_config == sources.UNSET:
+            # this is v1
             self._network_config = cmdline.read_initramfs_config()
+
             if not self._network_config:
+                # this is now v2
                 self._network_config = self.distro.generate_fallback_config()
+
             if self.ds_cfg.get('configure_secondary_nics'):
                 try:
                     # Mutate self._network_config to include secondary VNICs
@@ -219,6 +273,12 @@ class DataSourceOracle(sources.DataSource):
                     util.logexc(
                         LOG,
                         "Failed to fetch secondary network configuration!")
+
+            # we need to verify that the nic selected is not a netfail over
+            # device and, if it is a netfail master, then we need to avoid
+            # emitting any match by mac
+            _ensure_netfailover_safe(self._network_config)
+
         return self._network_config
 
 
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