bfd: T1183: initial CLI implementation

vyos@vyos# show protocols bfd
  peer 172.18.202.10 {
    local-address 172.18.201.10
    local-interface eth0.201
    shutdown
  }
  peer 172.18.202.12 {
    shutdown
  }

2 files changed, 134 insertions, 0 deletions

diff --git a/interface-definitions/protocols-bfd.xml b/interface-definitions/protocols-bfd.xml
new file mode 100644
index 000000000..c8b25eb2d
--- /dev/null
+++ b/interface-definitions/protocols-bfd.xml
@@ -0,0 +1,58 @@
+<?xml version="1.0"?>
+<!-- Bidirectional Forwarding Detection (BFD) configuration -->
+<interfaceDefinition>
+  <node name="protocols">
+    <children>
+      <node name="bfd" owner="${vyos_conf_scripts_dir}/protocols_bfd.py">
+        <properties>
+          <help>Bidirectional Forwarding Detection (BFD)</help>
+          <priority>820</priority>
+        </properties>
+        <children>
+          <tagNode name="peer">
+            <properties>
+              <help>Configures a new BFD peer to listen and talk to</help>
+              <valueHelp>
+                <format>ipv4</format>
+                <description>BFD peer IPv4 address</description>
+              </valueHelp>
+              <valueHelp>
+                <format>ipv6</format>
+                <description>BFD peer IPv6 address</description>
+              </valueHelp>
+            </properties>
+            <children>
+              <leafNode name="local-interface">
+                <properties>
+                  <help>Local interface to bind our peer listener to</help>
+                  <completionHelp>
+                    <script>${vyos_completion_dir}/list_interfaces.py</script>
+                  </completionHelp>
+                </properties>
+              </leafNode>
+              <leafNode name="local-address">
+                <properties>
+                  <help>Local address to bind our peer listener to</help>
+                  <valueHelp>
+                    <format>ipv4</format>
+                    <description>Local IPv4 address used to connect to the peer</description>
+                  </valueHelp>
+                  <valueHelp>
+                    <format>ipv6</format>
+                    <description>Local IPv6 address used to connect to the peer</description>
+                  </valueHelp>
+                </properties>
+              </leafNode>
+              <leafNode name="shutdown">
+                <properties>
+                  <help>Disable this peer</help>
+                  <valueless/>
+                </properties>
+              </leafNode>
+            </children>
+          </tagNode>
+        </children>
+      </node>
+    </children>
+  </node>
+</interfaceDefinition>
diff --git a/src/conf_mode/protocols_bfd.py b/src/conf_mode/protocols_bfd.py
new file mode 100755
index 000000000..7e137c484
--- /dev/null
+++ b/src/conf_mode/protocols_bfd.py
@@ -0,0 +1,76 @@
+#!/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 copy
+from vyos.config import Config
+
+default_config_data = {
+    'peers': []
+}
+
+def get_config():
+    bfd = copy.deepcopy(default_config_data)
+    conf = Config()
+    if not conf.exists('protocols bfd'):
+        return None
+    else:
+        conf.set_level('protocols bfd')
+
+    for peer in conf.list_nodes('peer'):
+        conf.set_level('protocols bfd peer {0}'.format(peer))
+        bfd_peer = {
+            'peer': peer,
+            'shutdown': False,
+            'local-interface': '',
+            'local-address': '',
+        }
+
+        # 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('local-interface'):
+            bfd_peer['local-interface'] = conf.return_value('local-interface')
+
+        # Check if peer has a local source address configured - this is mandatory for IPv6
+        if conf.exists('local-address'):
+            bfd_peer['local-address'] = conf.return_value('local-address')
+
+        bfd['peers'].append(bfd_peer)
+
+    print(bfd)
+    return bfd
+
+def verify(bfd):
+    return None
+
+def generate(bfd):
+    return None
+
+def apply(bfd):
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        sys.exit(1)