Azure, CloudStack: Support reading dhcp options from systemd-networkd.

Systems that used systemd-networkd's dhcp client would not be able to get
information on the Azure endpoint (placed in Option 245) or the CloudStack
server (in 'server_address').

The change here supports reading these files in /run/systemd/netif/leases.
The files declare that "This is private data. Do not parse.", but at this
point we do not have another option.

LP: #1718029

1 files changed, 42 insertions, 0 deletions

diff --git a/cloudinit/net/dhcp.py b/cloudinit/net/dhcp.py
index 05350639..0cba7032 100644
--- a/cloudinit/net/dhcp.py
+++ b/cloudinit/net/dhcp.py
@@ -4,6 +4,7 @@
 #
 # This file is part of cloud-init. See LICENSE file for license information.
 
+import configobj
 import logging
 import os
 import re
@@ -11,9 +12,12 @@ import re
 from cloudinit.net import find_fallback_nic, get_devicelist
 from cloudinit import temp_utils
 from cloudinit import util
+from six import StringIO
 
 LOG = logging.getLogger(__name__)
 
+NETWORKD_LEASES_DIR = '/run/systemd/netif/leases'
+
 
 class InvalidDHCPLeaseFileError(Exception):
     """Raised when parsing an empty or invalid dhcp.leases file.
@@ -118,4 +122,42 @@ def dhcp_discovery(dhclient_cmd_path, interface, cleandir):
     return parse_dhcp_lease_file(lease_file)
 
 
+def networkd_parse_lease(content):
+    """Parse a systemd lease file content as in /run/systemd/netif/leases/
+
+    Parse this (almost) ini style file even though it says:
+      # This is private data. Do not parse.
+
+    Simply return a dictionary of key/values."""
+
+    return dict(configobj.ConfigObj(StringIO(content), list_values=False))
+
+
+def networkd_load_leases(leases_d=None):
+    """Return a dictionary of dictionaries representing each lease
+    found in lease_d.i
+
+    The top level key will be the filename, which is typically the ifindex."""
+
+    if leases_d is None:
+        leases_d = NETWORKD_LEASES_DIR
+
+    ret = {}
+    if not os.path.isdir(leases_d):
+        return ret
+    for lfile in os.listdir(leases_d):
+        ret[lfile] = networkd_parse_lease(
+            util.load_file(os.path.join(leases_d, lfile)))
+    return ret
+
+
+def networkd_get_option_from_leases(keyname, leases_d=None):
+    if leases_d is None:
+        leases_d = NETWORKD_LEASES_DIR
+    leases = networkd_load_leases(leases_d=leases_d)
+    for ifindex, data in sorted(leases.items()):
+        if data.get(keyname):
+            return data[keyname]
+    return None
+
 # vi: ts=4 expandtab