Import BFD implementation from current. Implementation by Christian Poessinger et al.

1 files changed, 231 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..9ca194edd
--- /dev/null
+++ b/src/conf_mode/protocols_bfd.py
@@ -0,0 +1,231 @@
+#!/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.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 %}
+{% 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 peer.echo_mode %}echo-mode{% endif %}
+ {% if peer.echo_interval != '' %}echo-interval {{ peer.echo_interval }}{% endif %}
+ {% if not peer.shutdown %}no {% endif %}shutdown
+{% endfor -%}
+!
+"""
+
+default_config_data = {
+    'new_peers': [],
+    'old_peers' : []
+}
+
+# get configuration for BFD peer from proposed or effective configuration
+def get_bfd_peer_config(peer, conf_mode="proposed"):
+    conf = Config()
+    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,
+        'echo_interval': '',
+        'echo_mode': False,
+    }
+
+    # Check if individual peer is disabled
+    if conf_mode == "effective" and conf.exists_effective('shutdown'):
+        bfd_peer['shutdown'] = True
+    if conf_mode == "proposed" and conf.exists('shutdown'):
+        bfd_peer['shutdown'] = True
+
+    # Check if peer has a local source interface configured
+    if conf_mode == "effective" and conf.exists_effective('source interface'):
+        bfd_peer['src_if'] = conf.return_effective_value('source interface')
+    if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('source address'):
+        bfd_peer['src_addr'] = conf.return_effective_value('source address')
+    if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('multihop'):
+        bfd_peer['multihop'] = True
+    if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval receive'):
+        bfd_peer['rx_interval'] = conf.return_effective_value('interval receive')
+    if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval transmit'):
+        bfd_peer['tx_interval'] = conf.return_effective_value('interval transmit')
+    if conf_mode == "proposed" and 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_mode == "effective" and conf.exists_effective('interval multiplier'):
+        bfd_peer['multiplier'] = conf.return_effective_value('interval multiplier')
+    if conf_mode == "proposed" and conf.exists('interval multiplier'):
+        bfd_peer['multiplier'] = conf.return_value('interval multiplier')
+
+    # Configures the minimal echo receive transmission interval that this system is capable of handling
+    if conf_mode == "effective" and conf.exists_effective('interval echo-interval'):
+        bfd_peer['echo_interval'] = conf.return_effective_value('interval echo-interval')
+    if conf_mode == "proposed" and conf.exists('interval echo-interval'):
+        bfd_peer['echo_interval'] = conf.return_value('interval echo-interval')
+
+    # Enables or disables the echo transmission mode
+    if conf_mode == "effective" and conf.exists_effective('echo-mode'):
+        bfd_peer['echo_mode'] = True
+    if conf_mode == "proposed" and conf.exists('echo-mode'):
+        bfd_peer['echo_mode'] = True
+
+    return bfd_peer
+
+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)
+    for peer in conf.list_effective_nodes('peer'):
+        bfd['old_peers'].append(get_bfd_peer_config(peer, "effective"))
+
+    for peer in conf.list_nodes('peer'):
+        bfd['new_peers'].append(get_bfd_peer_config(peer))
+
+    # find deleted peers
+    set_new_peers = set(conf.list_nodes('peer'))
+    set_old_peers = set(conf.list_effective_nodes('peer'))
+    bfd['deleted_peers'] = set_old_peers - set_new_peers
+
+    return bfd
+
+def verify(bfd):
+    if bfd is None:
+        return None
+
+    # some variables to use later
+    conf = Config()
+
+    for peer in bfd['new_peers']:
+        # 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 and interface setting')
+
+        # multihop require source address
+        if peer['multihop'] and not peer['src_addr']:
+            raise ConfigError('Multihop require source address')
+
+        # multihop and echo-mode cannot be used together
+        if peer['multihop'] and peer['echo_mode']:
+            raise ConfigError('Multihop and echo-mode cannot be used together')
+
+        # multihop doesn't accept interface names
+        if peer['multihop'] and peer['src_if']:
+            raise ConfigError('Multihop and source interface cannot be used together')
+
+        # echo interval can be configured only with enabled echo-mode
+        if peer['echo_interval'] != '' and not peer['echo_mode']:
+            raise ConfigError('echo-interval can be configured only with enabled echo-mode')
+
+    # check if we deleted peers are not used in configuration
+    if conf.exists('protocols bgp'):
+        bgp_as = conf.list_nodes('protocols bgp')[0]
+
+        # check BGP neighbors
+        for peer in bfd['deleted_peers']:
+            if conf.exists('protocols bgp {0} neighbor {1} bfd'.format(bgp_as, peer)):
+                raise ConfigError('Cannot delete BFD peer {0}: it is used in BGP configuration'.format(peer))
+            if conf.exists('protocols bgp {0} neighbor {1} peer-group'.format(bgp_as, peer)):
+                peer_group = conf.return_value('protocols bgp {0} neighbor {1} peer-group'.format(bgp_as, peer))
+                if conf.exists('protocols bgp {0} peer-group {1} bfd'.format(bgp_as, peer_group)):
+                    raise ConfigError('Cannot delete BFD peer {0}: it belongs to BGP peer-group {1} with enabled BFD'.format(peer, peer_group))
+
+    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)