[bfd] T1183: Added some new functionality and fixed bugs in BFD:

* added option "echo-mode" and "echo-interval" for BFD peers
* added configuration check for usage "multihop" and "echo-mode"
* added configuration check for denying deletion BFD peers, which are used in BGP configuration
* fixed deleting/changing BFD peers with custom parameters (for example multihop, local-address, etc.)
* deleted wrong skipping of configuration check for "shutdown" BFD peers

1 files changed, 120 insertions, 59 deletions

diff --git a/src/conf_mode/protocols_bfd.py b/src/conf_mode/protocols_bfd.py
index 04549f4b4..98f38035a 100755
--- a/src/conf_mode/protocols_bfd.py
+++ b/src/conf_mode/protocols_bfd.py
@@ -31,7 +31,7 @@ config_tmpl = """
 !
 bfd
 {% for peer in old_peers -%}
- no peer {{ peer }}
+ 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 -%}
@@ -39,6 +39,8 @@ bfd
  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 -%}
 !
@@ -49,6 +51,86 @@ default_config_data = {
     '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()
@@ -60,56 +142,16 @@ def get_config():
     # 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_effective_nodes('peer'):
+        bfd['old_peers'].append(get_bfd_peer_config(peer, "effective"))
 
     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)
+        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
 
@@ -117,20 +159,39 @@ 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
+    # 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/interface setting')
-
-        # multihop doesn't accept interface names
-        if peer['multihop'] and peer['src_if']:
-            raise ConfigError('multihop does not accept interface names')
-
+                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')
+
+        # 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