[PATCH 3/4] Devices: add L2TPSessionDevice

[Jan Tluka]

This adds support for the L2TP sessions implemented as LNST Device
class.

Signed-off-by: Jan Tluka <jtluka(a)redhat.com&gt;
---
 lnst/Devices/L2TPSessionDevice.py | 118 ++++++++++++++++++++++++++++++
 lnst/Devices/__init__.py          |   4 +-
 2 files changed, 121 insertions(+), 1 deletion(-)
 create mode 100644 lnst/Devices/L2TPSessionDevice.py

diff --git a/lnst/Devices/L2TPSessionDevice.py b/lnst/Devices/L2TPSessionDevice.py
new file mode 100644
index 00000000..2cda9c96
--- /dev/null
+++ b/lnst/Devices/L2TPSessionDevice.py
@@ -0,0 +1,118 @@
+"""
+Defines the L2TPSessionDevice class.
+
+Copyright 2021 Red Hat, Inc.
+Licensed under the GNU General Public License, version 2 as
+published by the Free Software Foundation; see COPYING for details.
+"""
+
+__author__ = """
+jtluka(a)redhat.com (Jan Tluka)
+"""
+
+from pyroute2.netlink import NetlinkError
+from pyroute2.netlink.generic.l2tp import L2tp
+from lnst.Common.DeviceError import DeviceError, DeviceConfigError
+from lnst.Devices.Device import Device
+
+
+class L2TPSessionDevice(Device):
+    """
+    This device class allows user to create L2TP sessions for tunnels
+    previously created using the :any:`L2TPManager`.
+
+    .. code-block:: python
+
+        from lnst.Controller import BaseRecipe
+        from lnst.Controller.Requirements import HostReq
+        from lnst.RecipeCommon.L2TPManager import L2TPManager
+        from lnst.Devices import L2TPSessionDevice
+
+        class L2TPRecipe(BaseRecipe):
+            m1 = HostReq()
+
+            def test(self):
+                m1 = self.matched.m1
+                m1.l2tp = m1.init_class(L2TPManager)
+                m1.l2tp.create_tunnel(
+                        tunnel_id=1000,
+                        peer_tunnel_id=1000,
+                        encap="udp",
+                        local="192.168.200.1",
+                        remote="192.168.200.2",
+                        udp_sport=5000,
+                        udp_dport=5000
+
+                m1.session1 = L2TPSessionDevice(
+                        tunnel_id=1000,
+                        session_id=2000,
+                        peer_session_id=2000
+                )
+                m1.session1.up()
+    """
+    _name_template = "t_l2tp"
+    #: mandatory options for the device
+    _mandatory_opts = ["tunnel_id", "session_id",
"peer_session_id"]
+
+    def __init__(self, ifmanager, *args, **kwargs):
+        self._name = None
+        for i in self._mandatory_opts:
+            if i not in kwargs:
+                raise DeviceConfigError(
+                    "Option {} is mandatory for type {}".format(
+                        i, self.__class__.__name__
+                    )
+                )
+
+        self._tunnel_id = tunnel_id = kwargs["tunnel_id"]
+        self._session_id = kwargs["session_id"]
+        self._peer_session_id = kwargs["peer_session_id"]
+        self._ifmanager = ifmanager
+
+        super(L2TPSessionDevice, self).__init__(ifmanager)
+
+    def _create(self):
+        try:
+            self._l2tp_api = L2tp()
+        except NetlinkError:
+            raise DeviceError(
+                "Could not initialize pyroute's L2TP API. Please check if
l2tp_eth module is loaded."
+            )
+
+        session = {
+            "tunnel_id": self._tunnel_id,
+            "session_id": self._session_id,
+            "peer_session_id": self._peer_session_id,
+        }
+        if self._name is None:
+            self._name = session["ifname"] = self._ifmanager.assign_name(
+                self._name_template
+            )
+
+        try:
+            self._l2tp_api.create_session(**session)
+        except NetlinkError as e:
+            raise DeviceError(f"Could not create an L2TP session: {e}")
+
+    def destroy(self):
+        self._l2tp_api.delete_session(self._tunnel_id, self._session_id)
+        return True
+
+    @Device.name.getter
+    def name(self):
+        try:
+            return super(L2TPSessionDevice, self).name
+        except:
+            return self._name
+
+    @property
+    def session_id(self):
+        return self._session_id
+
+    @property
+    def peer_session_id(self):
+        return self._peer_session_id
+
+    @property
+    def tunnel_id(self):
+        return self._tunnel_id
diff --git a/lnst/Devices/__init__.py b/lnst/Devices/__init__.py
index 4f68cb50..5ffed58e 100644
--- a/lnst/Devices/__init__.py
+++ b/lnst/Devices/__init__.py
@@ -14,6 +14,7 @@ from lnst.Devices.VtiDevice import VtiDevice, Vti6Device
 from lnst.Devices.VethDevice import VethDevice, PairedVethDevice
 from lnst.Devices.VethPair import VethPair
 from lnst.Devices.MacsecDevice import MacsecDevice
+from lnst.Devices.L2TPSessionDevice import L2TPSessionDevice
 from lnst.Devices.RemoteDevice import RemoteDevice, remotedev_decorator
 
 device_classes = [
@@ -32,7 +33,8 @@ device_classes = [
         ("Vti6Device", Vti6Device),
         ("BondDevice", BondDevice),
         ("TeamDevice", TeamDevice),
-        ("MacsecDevice", MacsecDevice)]
+        ("MacsecDevice", MacsecDevice),
+        ("L2TPSessionDevice", L2TPSessionDevice)]
 
 for name, cls in device_classes:
     globals()[name] = remotedev_decorator(cls)
-- 
2.26.3