broadcast-relay: T2712: migrate to get_config_dict()

Add additional verify() stage to check that the relaying interface actually
exists on the system.

2 files changed, 35 insertions, 102 deletions

diff --git a/data/templates/bcast-relay/udp-broadcast-relay.tmpl b/data/templates/bcast-relay/udp-broadcast-relay.tmpl
index 3d8c3fe94..d0c7d8bf9 100644
--- a/data/templates/bcast-relay/udp-broadcast-relay.tmpl
+++ b/data/templates/bcast-relay/udp-broadcast-relay.tmpl
@@ -4,4 +4,4 @@
 {%- if description %}
 # Comment: {{ description }}
 {% endif %}
-DAEMON_ARGS="{% if address %}-s {{ address }} {% endif %}{{ id }} {{ port }} {{ interfaces | join(' ') }}"
+DAEMON_ARGS="{{ '-s ' + address if address is defined }} {{ instance }} {{ port }} {{ interface | join(' ') }}"
diff --git a/src/conf_mode/bcast_relay.py b/src/conf_mode/bcast_relay.py
index 5c7294296..a3e141a00 100755
--- a/src/conf_mode/bcast_relay.py
+++ b/src/conf_mode/bcast_relay.py
@@ -15,151 +15,84 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
-import fnmatch
 
+from glob import glob
+from netifaces import interfaces
 from sys import exit
-from copy import deepcopy
 
 from vyos.config import Config
-from vyos import ConfigError
 from vyos.util import call
 from vyos.template import render
-
+from vyos import ConfigError
 from vyos import airbag
 airbag.enable()
 
-config_file = r'/etc/default/udp-broadcast-relay'
-
-default_config_data = {
-    'disabled': False,
-    'instances': []
-}
+config_file_base = r'/etc/default/udp-broadcast-relay'
 
 def get_config():
-    relay = deepcopy(default_config_data)
     conf = Config()
     base = ['service', 'broadcast-relay']
 
-    if not conf.exists(base):
-        return None
-    else:
-        conf.set_level(base)
-
-    # Service can be disabled by user
-    if conf.exists('disable'):
-        relay['disabled'] = True
-        return relay
-
-    # Parse configuration of each individual instance
-    if conf.exists('id'):
-        for id in conf.list_nodes('id'):
-            conf.set_level(base + ['id', id])
-            config = {
-                'id': id,
-                'disabled': False,
-                'address': '',
-                'description': '',
-                'interfaces': [],
-                'port': ''
-            }
-
-            # Check if individual broadcast relay service is disabled
-            if conf.exists(['disable']):
-                config['disabled'] = True
-
-            # Source IP of forwarded packets, if empty original senders address is used
-            if conf.exists(['address']):
-                config['address'] = conf.return_value(['address'])
-
-            # A description for each individual broadcast relay service
-            if conf.exists(['description']):
-                config['description'] = conf.return_value(['description'])
-
-            # UDP port to listen on for broadcast frames
-            if conf.exists(['port']):
-                config['port'] = conf.return_value(['port'])
-
-            # Network interfaces to listen on for broadcast frames to be relayed
-            if conf.exists(['interface']):
-                config['interfaces'] = conf.return_values(['interface'])
-
-            relay['instances'].append(config)
-
+    relay = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=True)
     return relay
 
 def verify(relay):
-    if relay is None:
-        return None
-
-    if relay['disabled']:
+    if not relay or 'disabled' in relay:
         return None
 
-    for r in relay['instances']:
+    for instance, config in relay.get('id', {}).items():
         # we don't have to check this instance when it's disabled
-        if r['disabled']:
+        if 'disabled' in config:
             continue
 
         # we certainly require a UDP port to listen to
-        if not r['port']:
-            raise ConfigError('UDP broadcast relay "{0}" requires a port number'.format(r['id']))
+        if 'port' not in config:
+            raise ConfigError(f'Port number mandatory for udp broadcast relay "{instance}"')
 
+        # if only oone interface is given it's a string -> move to list
+        if isinstance(config.get('interface', []), str):
+            config['interface'] = [ config['interface'] ]
         # Relaying data without two interface is kinda senseless ...
-        if len(r['interfaces']) < 2:
-            raise ConfigError('UDP broadcast relay "id {0}" requires at least 2 interfaces'.format(r['id']))
+        if len(config.get('interface', [])) < 2:
+            raise ConfigError('At least two interfaces are required for udp broadcast relay "{instance}"')
 
-    return None
+        for interface in config.get('interface', []):
+            if interface not in interfaces():
+                raise ConfigError('Interface "{interface}" does not exist!')
 
+    return None
 
 def generate(relay):
-    if relay is None:
+    if not relay or 'disabled' in relay:
         return None
 
-    config_dir = os.path.dirname(config_file)
-    config_filename = os.path.basename(config_file)
-    active_configs = []
-
-    for config in fnmatch.filter(os.listdir(config_dir), config_filename + '*'):
-        # determine prefix length to identify service instance
-        prefix_len = len(config_filename)
-        active_configs.append(config[prefix_len:])
-
-    # sort our list
-    active_configs.sort()
+    for config in glob(config_file_base + '*'):
+        os.remove(config)
 
-    # delete old configuration files
-    for id in active_configs[:]:
-        if os.path.exists(config_file + id):
-            os.unlink(config_file + id)
-
-    # If the service is disabled, we can bail out here
-    if relay['disabled']:
-        print('Warning: UDP broadcast relay service will be deactivated because it is disabled')
-        return None
-
-    for r in relay['instances']:
-        # Skip writing instance config when it's disabled
-        if r['disabled']:
+    for instance, config in relay.get('id').items():
+        # we don't have to check this instance when it's disabled
+        if 'disabled' in config:
             continue
 
-        # configuration filename contains instance id
-        file = config_file + str(r['id'])
-        render(file, 'bcast-relay/udp-broadcast-relay.tmpl', r)
+        config['instance'] = instance
+        render(config_file_base + instance, 'bcast-relay/udp-broadcast-relay.tmpl', config)
 
     return None
 
 def apply(relay):
     # first stop all running services
-    call('systemctl stop udp-broadcast-relay@{1..99}.service')
+    call('systemctl stop udp-broadcast-relay@*.service')
 
-    if (relay is None) or relay['disabled']:
+    if not relay or 'disable' in relay:
         return None
 
     # start only required service instances
-    for r in relay['instances']:
-        # Don't start individual instance when it's disabled
-        if r['disabled']:
+    for instance, config in relay.get('id').items():
+        # we don't have to check this instance when it's disabled
+        if 'disabled' in config:
             continue
-        call('systemctl start udp-broadcast-relay@{0}.service'.format(r['id']))
+
+        call(f'systemctl start udp-broadcast-relay@{instance}.service')
 
     return None