sambacc: add ad dc functions for interface filtering

These functions will later be used by the provisioning (sub)command to
filter interfaces without having to know exactly what is on the target
system.

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

sambacc/addc.py

@@ -17,9 +17,11 @@
 #
 
 import logging
+import re
 import subprocess
 import typing
 
+from sambacc import config
 from sambacc import samba_cmds
 
 _logger = logging.getLogger(__name__)
@@ -215,3 +217,24 @@ def _group_add_members_cmd(group_name: str, members: list[str]) -> list[str]:
         ",".join(members),
     ].argv()
     return cmd
+
+
+def _ifnames() -> list[str]:
+    import socket
+
+    return [iface for _, iface in socket.if_nameindex()]
+
+
+def filtered_interfaces(
+    ic: config.DCInterfaceConfig, ifnames: typing.Optional[list[str]] = None
+) -> list[str]:
+    _include = re.compile(ic.include_pattern or "^.*$")
+    _exclude = re.compile(ic.exclude_pattern or "^$")
+    if ifnames is None:
+        ifnames = _ifnames()
+    return [
+        name
+        for name in ifnames
+        if (name == "lo")
+        or (_include.match(name) and not _exclude.match(name))
+    ]