l2tpv3: T1923: implementation in XML/Python

Tested using:

R1:
---

set interfaces l2tpv3 l2tpeth10 address '2001:db8:beef::1/64'
set interfaces l2tpv3 l2tpeth10 address '100.0.0.1/24'
set interfaces l2tpv3 l2tpeth10 destination-port '3000'
set interfaces l2tpv3 l2tpeth10 encapsulation 'udp'
set interfaces l2tpv3 l2tpeth10 local-ip '172.18.201.10'
set interfaces l2tpv3 l2tpeth10 peer-session-id '10'
set interfaces l2tpv3 l2tpeth10 peer-tunnel-id '100'
set interfaces l2tpv3 l2tpeth10 remote-ip '172.18.204.10'
set interfaces l2tpv3 l2tpeth10 session-id '20'
set interfaces l2tpv3 l2tpeth10 source-port '6000'
set interfaces l2tpv3 l2tpeth10 tunnel-id '200'

R2:
---

set interfaces l2tpv3 l2tpeth10 address '2001:db8:beef::2/64'
set interfaces l2tpv3 l2tpeth10 address '100.0.0.2/24'
set interfaces l2tpv3 l2tpeth10 destination-port '6000'
set interfaces l2tpv3 l2tpeth10 encapsulation 'udp'
set interfaces l2tpv3 l2tpeth10 local-ip '172.18.204.10'
set interfaces l2tpv3 l2tpeth10 peer-session-id '20'
set interfaces l2tpv3 l2tpeth10 peer-tunnel-id '200'
set interfaces l2tpv3 l2tpeth10 remote-ip '172.18.201.10'
set interfaces l2tpv3 l2tpeth10 session-id '10'
set interfaces l2tpv3 l2tpeth10 source-port '3000'
set interfaces l2tpv3 l2tpeth10 tunnel-id '100'

1 files changed, 228 insertions, 0 deletions

diff --git a/src/conf_mode/interfaces-l2tpv3.py b/src/conf_mode/interfaces-l2tpv3.py
new file mode 100755
index 000000000..62d802b39
--- /dev/null
+++ b/src/conf_mode/interfaces-l2tpv3.py
@@ -0,0 +1,228 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2019 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from sys import exit
+from copy import deepcopy
+
+from vyos.config import Config
+from vyos.ifconfig import L2TPv3If, Interface
+from vyos import ConfigError
+from netifaces import interfaces
+
+default_config_data = {
+    'address': [],
+    'deleted': False,
+    'description': '',
+    'disable': False,
+    'encapsulation': 'udp',
+    'local_address': '',
+    'local_port': 5000,
+    'intf': '',
+    'mtu': 1488,
+    'peer_session_id': '',
+    'peer_tunnel_id': '',
+    'remote_address': '',
+    'remote_port': 5000,
+    'session_id': '',
+    'tunnel_id': ''
+}
+
+def get_config():
+    l2tpv3 = deepcopy(default_config_data)
+    conf = Config()
+
+    # determine tagNode instance
+    try:
+        l2tpv3['intf'] = os.environ['VYOS_TAGNODE_VALUE']
+    except KeyError as E:
+        print("Interface not specified")
+
+    # Check if interface has been removed
+    if not conf.exists('interfaces l2tpv3 ' + l2tpv3['intf']):
+        l2tpv3['deleted'] = True
+        return l2tpv3
+
+    # set new configuration level
+    conf.set_level('interfaces l2tpv3 ' + l2tpv3['intf'])
+
+    # retrieve configured interface addresses
+    if conf.exists('address'):
+        l2tpv3['address'] = conf.return_values('address')
+
+    # retrieve interface description
+    if conf.exists('description'):
+        l2tpv3['description'] = conf.return_value('description')
+
+    # get tunnel destination port
+    if conf.exists('destination-port'):
+        l2tpv3['remote_port'] = int(conf.return_value('destination-port'))
+
+    # Disable this interface
+    if conf.exists('disable'):
+        l2tpv3['disable'] = True
+
+    # get tunnel encapsulation type
+    if conf.exists('encapsulation'):
+        l2tpv3['encapsulation'] = conf.return_value('encapsulation')
+
+    # get tunnel local ip address
+    if conf.exists('local-ip'):
+        l2tpv3['local_address'] = conf.return_value('local-ip')
+
+    # Maximum Transmission Unit (MTU)
+    if conf.exists('mtu'):
+        l2tpv3['mtu'] = int(conf.return_value('mtu'))
+
+    # Remote session id
+    if conf.exists('peer-session-id'):
+        l2tpv3['peer_session_id'] = conf.return_value('peer-session-id')
+
+    # Remote tunnel id
+    if conf.exists('peer-tunnel-id'):
+        l2tpv3['peer_tunnel_id'] = conf.return_value('peer-tunnel-id')
+
+    # Remote address of L2TPv3 tunnel
+    if conf.exists('remote-ip'):
+        l2tpv3['remote_address'] = conf.return_value('remote-ip')
+
+    # Local session id
+    if conf.exists('session-id'):
+        l2tpv3['session_id'] = conf.return_value('session-id')
+
+    # get local tunnel port
+    if conf.exists('source-port'):
+        l2tpv3['local_port'] = conf.return_value('source-port')
+
+    # get local tunnel id
+    if conf.exists('tunnel-id'):
+        l2tpv3['tunnel_id'] = conf.return_value('tunnel-id')
+
+    return l2tpv3
+
+
+def verify(l2tpv3):
+    if l2tpv3['deleted']:
+        # bail out early
+        return None
+
+    if not l2tpv3['local_address']:
+        raise ConfigError('Must configure the l2tpv3 local-ip for {}'.format(l2tpv3['intf']))
+
+    if not l2tpv3['remote_address']:
+        raise ConfigError('Must configure the l2tpv3 remote-ip for {}'.format(l2tpv3['intf']))
+
+    if not l2tpv3['tunnel_id']:
+        raise ConfigError('Must configure the l2tpv3 tunnel-id for {}'.format(l2tpv3['intf']))
+
+    if not l2tpv3['peer_tunnel_id']:
+        raise ConfigError('Must configure the l2tpv3 peer-tunnel-id for {}'.format(l2tpv3['intf']))
+
+    if not l2tpv3['session_id']:
+        raise ConfigError('Must configure the l2tpv3 session-id for {}'.format(l2tpv3['intf']))
+
+    if not l2tpv3['peer_session_id']:
+        raise ConfigError('Must configure the l2tpv3 peer-session-id for {}'.format(l2tpv3['intf']))
+
+    return None
+
+
+def generate(l2tpv3):
+    if l2tpv3['deleted']:
+        # bail out early
+        return None
+
+    # initialize kernel module if not loaded
+    if not os.path.isdir('/sys/module/l2tp_eth'):
+        if os.system('modprobe l2tp_eth') != 0:
+            raise ConfigError("failed loading l2tp_eth kernel module")
+
+    if not os.path.isdir('/sys/module/l2tp_netlink'):
+        if os.system('modprobe l2tp_netlink') != 0:
+            raise ConfigError("failed loading l2tp_netlink kernel module")
+
+    if not os.path.isdir('/sys/module/l2tp_ip'):
+        if os.system('modprobe l2tp_ip') != 0:
+            raise ConfigError("failed loading l2tp_ip kernel module")
+
+    if l2tpv3['encapsulation'] == 'ip':
+        if not os.path.isdir('/sys/module/l2tp_ip'):
+            if os.system('modprobe l2tp_ip') != 0:
+                raise ConfigError("failed loading l2tp_ip kernel module")
+
+        if not os.path.isdir('/sys/module/l2tp_ip6 '):
+            if os.system('modprobe l2tp_ip6 ') != 0:
+                raise ConfigError("failed loading l2tp_ip6 kernel module")
+
+    return None
+
+
+def apply(l2tpv3):
+    # Check if L2TPv3 interface already exists
+    if l2tpv3['intf'] in interfaces():
+        l = L2TPv3If(l2tpv3['intf'])
+        # L2TPv3 is super picky and the tunnel always needs to be recreated,
+        # thus we can simply always delete it first.
+        l.remove()
+
+
+    if not l2tpv3['deleted']:
+        # L2TPv3 interface needs to be created on-block
+        # instead of passing a ton of arguments, I just use a dict
+        # that is managed by vyos.ifconfig
+        conf = deepcopy(L2TPv3If.get_config())
+
+        conf['peer_tunnel_id'] = l2tpv3['peer_tunnel_id']
+        conf['local_port'] = l2tpv3['local_port']
+        conf['remote_port'] = l2tpv3['remote_port']
+        conf['encapsulation'] = l2tpv3['encapsulation']
+        conf['local_address'] = l2tpv3['local_address']
+        conf['remote_address'] = l2tpv3['remote_address']
+        conf['session_id'] = l2tpv3['session_id']
+        conf['tunnel_id'] = l2tpv3['tunnel_id']
+        conf['peer_session_id'] = l2tpv3['peer_session_id']
+
+        # Finally create the new interface
+        l = L2TPv3If(l2tpv3['intf'], config=conf)
+        # update interface description used e.g. by SNMP
+        l.set_alias(l2tpv3['description'])
+        # Maximum Transfer Unit (MTU)
+        l.set_mtu(l2tpv3['mtu'])
+
+        # Configure interface address(es) - no need to implicitly delete the
+        # old addresses as they have already been removed by deleting the
+        # interface above
+        for addr in l2tpv3['address']:
+            l.add_addr(addr)
+
+        # As the interface is always disabled first when changing parameters
+        # we will only re-enable the interface if it is not  administratively
+        # disabled
+        if not l2tpv3['disable']:
+            l.set_state('up')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)