ietf-system: Support read of NTPsec configuration

1 files changed, 154 insertions, 2 deletions

diff --git a/ncserver/module/system.py b/ncserver/module/system.py
index c27b3a0..d5c097c 100644
--- a/ncserver/module/system.py
+++ b/ncserver/module/system.py
@@ -85,15 +85,165 @@ _LOCATION_PATH = '/etc/netconf/location.txt'
 """The file path for the contents of /sys:system/location."""
 
 
+class NTPServer:  # pylint: disable=R0902
+    """Represents an NTP server entry."""
+    def __init__(self, host: str, **kwargs):
+        """Create a new NTP server entry.
+
+        :param str host:
+        The host, in IP or DNS form.
+        """
+        self.host = host
+        self.mode = kwargs.pop('mode', 'pool')
+        if self.mode in ('server', 'peer'):
+            self.key = kwargs.pop('key', None)
+        else:
+            self.key = None
+        self.burst = kwargs.pop('burst', False)
+        self.iburst = kwargs.pop('iburst', False)
+        self.version = kwargs.pop('version', None)
+        self.prefer = kwargs.pop('prefer', False)
+        self.minpoll = kwargs.pop('minpoll', None)
+        self.maxpoll = kwargs.pop('maxpoll', None)
+        if self.mode == 'poll':
+            self.preempt = kwargs.pop('preempt', False)
+        else:
+            self.preempt = False
+
+    def __repr__(self):
+        """Return a representation of this object."""
+        args = {'mode': '"' + self.mode + '"'}
+        if self.burst:
+            args['burst'] = True
+        if self.iburst:
+            args['iburst'] = True
+        if self.version is not None:
+            args['version'] = '"' + self.version + '"'
+        if self.prefer:
+            args['prefer'] = True
+        if self.minpoll is not None:
+            args['minpoll'] = '"' + self.minpoll + '"'
+        if self.maxpoll is not None:
+            args['maxpoll'] = '"' + self.maxpoll + '"'
+
+        if self.mode in ('server', 'peer') and self.key is not None:
+            args['key'] = '"' + self.key + '"'
+        if self.mode == 'poll' and self.preempt:
+            args['preempt'] = True
+
+        nondef_args = ', '.join(
+                ['{}={}'.format(*item) for item in args.items()]
+        )
+        return "NTPServer('{host}', {nondef_args})".format(host=self.host,
+                nondef_args=nondef_args)
+
+    def __str__(self):
+        """Return the configuration line for this server."""
+        line = self.mode + ' '
+
+        if ':' in self.host and '[' not in self.host:
+            if '%' in self.host:
+                addr, dev = self.host.split('%')
+                line += '[' + addr + ']%' + dev
+            else:
+                line += '[' + self.host + ']'
+        else:
+            line += self.host
+
+        if self.mode in ('server', 'peer') and self.key is not None:
+            line += ' key ' + self.key
+
+        if self.mode in ('pool', 'server'):
+            if self.burst:
+                line += ' burst'
+            if self.iburst:
+                line += ' iburst'
+
+        if self.version is not None:
+            line += ' version ' + str(self.version)
+
+        if self.prefer:
+            line += ' prefer'
+
+        if self.minpoll is not None:
+            line += ' minpoll ' + self.minpoll
+        if self.maxpoll is not None:
+            line += ' maxpoll ' + self.maxpoll
+
+        if self.mode == 'pool' and self.preempt:
+            line += ' preempt'
+
+        return line
+
+    @classmethod
+    def from_line(cls, line: str):
+        """Create an NTPServer object from a configuration file line."""
+        tokens = line.strip().split(' ')
+        tokens.reverse()
+
+        kwargs = {'mode': tokens.pop()}
+        host = tokens.pop()
+
+        bool_keys = ('burst', 'iburst', 'prefer', 'preempt')
+        value_keys = ('key', 'version', 'minpoll', 'maxpoll')
+
+        while len(tokens) > 0:
+            key = tokens.pop()
+            if key in bool_keys:
+                kwargs[key] = True
+            elif key in value_keys:
+                kwargs[key] = tokens.pop()
+            else:
+                LOGGER.warning('unknown NTP server conf key: %s', key)
+
+        return cls(host, **kwargs)
+
+
+def _parse_ntp_config() -> dict:
+    """Parse /etc/ntp.conf and return the configuration.
+
+    The return value is a dictionary with the following keys:
+
+        * servers: a list of NTPServer objects.
+    """
+    conf = open('/etc/ntp.conf', 'r')
+    lines = conf.readlines()
+    conf.close()
+
+    result = {'servers': list()}
+
+    for line in lines:
+        line.strip()
+        if line.startswith('#') or len(line) == 0:
+            continue
+        if any([line.startswith(word) for word in ('server', 'pool', 'peer')]):
+            result['servers'].append(NTPServer.from_line(line))
+        else:
+            LOGGER.warning('unhandled NTP configuration line: %s', line)
+
+    return result
+
+
 def _parse_ntp_conf_to(sys_node):
     """Parse NTP configuration into /sys:system/ntp format."""
     root = util.subelm(sys_node, 'sys:ntp')
 
-    if not os.path.exists('/etc/ntpsec/ntp.conf'):
+    if not os.path.exists('/etc/ntp.conf'):
         root.append(util.leaf_elm('sys:enabled', 'false'))
         return
 
-    # XXX TODO: parse NTP configuration.
+    conf = _parse_ntp_config()
+    for server in conf['servers']:
+        serv_node = util.subelm(root, 'sys:server')
+        serv_node.append(util.leaf_elm('sys:name', server.host))
+        serv_node.append(util.leaf_elm('sys:association-type', server.mode))
+        serv_node.append(util.leaf_elm('sys:iburst',
+                                       str(server.iburst).lower()))
+        serv_node.append(util.leaf_elm('sys:prefer',
+                                       str(server.prefer).lower()))
+        udp = util.subelm(serv_node, 'sys:udp')
+        udp.append(util.leaf_elm('sys:address', server.host))
+    return
 
 
 def _parse_resolv_conf() -> dict:
@@ -318,6 +468,8 @@ def _edit_dns_search(session, rpc, node, def_op, curr: dict):
 
 
 def _edit_dns_server(session, rpc, node, def_op, curr: dict):
+    # yes, this function is too complex.
+    # pylint: disable=R0912,R0914,R0915
     """Edit DNS nameserver configuration."""
     operation = node_operation(node, def_op)
     xmlmap = {'':  'urn:ietf:params:xml:ns:yang:ietf-system'}