labgrid/driver/power: add poe-mib backend

The PoE MiB backend uses SNMP enable and disable PoE on a switch port.
Compatibility was tested on a Cisco CBS350.

Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>

doc/configuration.rst

@@ -233,6 +233,9 @@ Currently available are:
   Controls TP-Link power strips via `python-kasa
   <https://github.com/python-kasa/python-kasa>`_.
 
+``poe_mib``
+  Controls PoE switches using the PoE SNMP administration MiBs.
+
 Used by:
   - `NetworkPowerDriver`_
 

labgrid/driver/power/poe_mib.py

@@ -0,0 +1,27 @@
+""" tested with Cisco CBS350, should be compatible with switches implementing the PoE administration MiB"""
+
+from ..exception import ExecutionError
+from ...util.snmp import SimpleSNMP
+
+OID = "1.3.6.1.2.1.105.1.1.1.3.1"
+
+def power_set(host, port, index, value):
+    _snmp = SimpleSNMP(host, 'private', port=port)
+    outlet_control_oid = "{}.{}".format(OID, index)
+
+    oid_value = "1" if value else "2"
+
+    _snmp.set(outlet_control_oid, oid_value)
+
+def power_get(host, port, index):
+    _snmp = SimpleSNMP(host, 'private', port=port)
+    output_status_oid = "{}.{}".format(OID, index)
+
+    value = _snmp.get(output_status_oid)
+
+    if value == 1:  # On
+        return True
+    if value == 2:  # Off
+        return False
+
+    raise ExecutionError("failed to get SNMP value")

tests/test_powerdriver.py

@@ -265,3 +265,7 @@ def test_import_backend_tplink(self):
     def test_import_backend_siglent(self):
         pytest.importorskip("vxi11")
         import labgrid.driver.power.siglent
+
+    def test_import_backend_poe_mib(self):
+        pytest.importorskip("pysnmp")
+        import labgrid.driver.power.poe_mib