1 files changed, 166 insertions, 0 deletions
diff --git a/src/conf_mode/protocols_bfd.py b/src/conf_mode/protocols_bfd.py
new file mode 100755
index 000000000..04549f4b4
--- /dev/null
+++ b/src/conf_mode/protocols_bfd.py
@@ -0,0 +1,166 @@
+#!/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 sys
+import jinja2
+import copy
+import os
+import vyos.validate
+
+from vyos import ConfigError
+from vyos.config import Config
+
+config_file = r'/tmp/bfd.frr'
+
+# Please be careful if you edit the template.
+config_tmpl = """
+!
+bfd
+{% for peer in old_peers -%}
+ no peer {{ peer }}
+{% endfor -%}
+!
+{% for peer in new_peers -%}
+ peer {{ peer.remote }}{% if peer.multihop %} multihop{% endif %}{% if peer.src_addr %} local-address {{ peer.src_addr }}{% endif %}{% if peer.src_if %} interface {{ peer.src_if }}{% endif %}
+ detect-multiplier {{ peer.multiplier }}
+ receive-interval {{ peer.rx_interval }}
+ transmit-interval {{ peer.tx_interval }}
+ {% if not peer.shutdown %}no {% endif %}shutdown
+{% endfor -%}
+!
+"""
+
+default_config_data = {
+    'new_peers': [],
+    'old_peers' : []
+}
+
+def get_config():
+    bfd = copy.deepcopy(default_config_data)
+    conf = Config()
+    if not (conf.exists('protocols bfd') or conf.exists_effective('protocols bfd')):
+        return None
+    else:
+        conf.set_level('protocols bfd')
+
+    # as we have to use vtysh to talk to FRR we also need to know
+    # which peers are gone due to a config removal - thus we read in
+    # all peers (active or to delete)
+    bfd['old_peers'] = conf.list_effective_nodes('peer')
+
+    for peer in conf.list_nodes('peer'):
+        conf.set_level('protocols bfd peer {0}'.format(peer))
+        bfd_peer = {
+            'remote': peer,
+            'shutdown': False,
+            'src_if': '',
+            'src_addr': '',
+            'multiplier': '3',
+            'rx_interval': '300',
+            'tx_interval': '300',
+            'multihop': False
+        }
+
+        # Check if individual peer is disabled
+        if conf.exists('shutdown'):
+            bfd_peer['shutdown'] = True
+
+        # Check if peer has a local source interface configured
+        if conf.exists('source interface'):
+            bfd_peer['src_if'] = conf.return_value('source interface')
+
+        # Check if peer has a local source address configured - this is mandatory for IPv6
+        if conf.exists('source address'):
+            bfd_peer['src_addr'] = conf.return_value('source address')
+
+        # Tell BFD daemon that we should expect packets with TTL less than 254
+        # (because it will take more than one hop) and to listen on the multihop
+        # port (4784)
+        if conf.exists('multihop'):
+            bfd_peer['multihop'] = True
+
+        # Configures the minimum interval that this system is capable of receiving
+        # control packets. The default value is 300 milliseconds.
+        if conf.exists('interval receive'):
+            bfd_peer['rx_interval'] = conf.return_value('interval receive')
+
+        # The minimum transmission interval (less jitter) that this system wants
+        # to use to send BFD control packets.
+        if conf.exists('interval transmit'):
+            bfd_peer['tx_interval'] = conf.return_value('interval transmit')
+
+        # Configures the detection multiplier to determine packet loss. The remote
+        # transmission interval will be multiplied by this value to determine the
+        # connection loss detection timer. The default value is 3.
+        if conf.exists('interval multiplier'):
+            bfd_peer['multiplier'] = conf.return_value('interval multiplier')
+
+        bfd['new_peers'].append(bfd_peer)
+
+    return bfd
+
+def verify(bfd):
+    if bfd is None:
+        return None
+
+    for peer in bfd['new_peers']:
+        # Bail out early if peer is shutdown
+        if peer['shutdown']:
+            continue
+
+        # IPv6 peers require an explicit local address/interface combination
+        if vyos.validate.is_ipv6(peer['remote']):
+            if not (peer['src_if'] and peer['src_addr']):
+                raise ConfigError('BFD IPv6 peers require explicit local address/interface setting')
+
+        # multihop doesn't accept interface names
+        if peer['multihop'] and peer['src_if']:
+            raise ConfigError('multihop does not accept interface names')
+
+
+    return None
+
+def generate(bfd):
+    if bfd is None:
+        return None
+
+    return None
+
+def apply(bfd):
+    if bfd is None:
+        return None
+
+    tmpl = jinja2.Template(config_tmpl)
+    config_text = tmpl.render(bfd)
+    with open(config_file, 'w') as f:
+        f.write(config_text)
+
+    os.system("sudo vtysh -d bfdd -f " + config_file)
+    if os.path.exists(config_file):
+        os.remove(config_file)
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        sys.exit(1)