dns: T5144: Modernize dynamic dns operation

Apply next round of configuration tree updates to 'service dns dynamic'
with the following changes:

- Migrate `service dns dynamic interface <interface> [use-web]`
       to `service dns dynamic address <interface>`
       or `service dns dynamic address web [web-options]`
  This communicates the intent that dynamic dns IP address is detected
  in only one way - using the `<interface>` or using an external web
  request, not both.
- When using external web request, (`service dns dynamic address web`),
  external url is optional (`web-options url`). Ddclient defaults are
  used when unspecified,
- Rename all config `login` to `username` for consistency and also to
  align better with alternative ddclient backends in consideration.
- Apply global 'ipv6-enable' to per service 'ip-version: ipv6'. Selecting
  usage of IPv4 or IPv6 (or both simultaneously) is now at per service
  (protocol) level instead of global level. This allows more control on
  the ability to select IPv4 in some cases and IPv6 in some other cases
  wherever supported by the underlying ddclient protocol.
- While the IP address (and by extension, the detection mechanism) is
  global, the way it is applied to a particular ddclient protocol depends
  on whether it supports IPv4 or IPv6 or both.
- Related to the above, this also prevents generating incorrect config
  file (`ddclient.conf`) with multiple global sections leading to an
  unpredictable behavior of ddclient.
- Implement provider (protocol) specific custom tweaks whenever possible
  (e.g., `zone`, `username`, `server` are not necessary in all cases).
- Move service name from a combination of 'protocol' (with protocol
  config autodetected) and custom (with protocol config specified) to a
  single 'service' key. This allows for consisent setup of multiple
  config for the same ddclient protocol (with different options and
  credentials). This also avoid ambiguity with usual networking term
  'protocol' and ddclient specific term 'protocol' (and can change with
  a move to a different backend).
- Apply upfront XML constraints and validations consistently wherever
  applicable.
- RFC2136 specific change: Rename rfc2136 config `record` to `host-name`
  for consistency.
- Cloudflare specific change: While ddclient still supports authenticating
  with email and global auth key, skipping `username` in config will
  indicate the intent to use API token authentication (with special
  'token' literal as `username`).

1 files changed, 45 insertions, 73 deletions

diff --git a/src/conf_mode/dynamic_dns.py b/src/conf_mode/dynamic_dns.py
index 426e3d693..879086cc4 100755
--- a/src/conf_mode/dynamic_dns.py
+++ b/src/conf_mode/dynamic_dns.py
@@ -29,20 +29,14 @@ airbag.enable()
 
 config_file = r'/run/ddclient/ddclient.conf'
 
-# Mapping of service name to service protocol
-default_service_protocol = {
-    'afraid': 'freedns',
-    'changeip': 'changeip',
-    'cloudflare': 'cloudflare',
-    'dnspark': 'dnspark',
-    'dslreports': 'dslreports1',
-    'dyndns': 'dyndns2',
-    'easydns': 'easydns',
-    'namecheap': 'namecheap',
-    'noip': 'noip',
-    'sitelutions': 'sitelutions',
-    'zoneedit': 'zoneedit1'
-}
+# Protocols that require zone
+zone_allowed = ['cloudflare', 'godaddy', 'hetzner', 'gandi', 'nfsn']
+
+# Protocols that do not require username
+username_unnecessary = ['1984', 'cloudflare', 'cloudns', 'duckdns', 'freemyip', 'hetzner', 'keysystems', 'njalla']
+
+# Protocols that support both IPv4 and IPv6
+dualstack_supported = ['cloudflare', 'dyndns2', 'freedns', 'njalla']
 
 def get_config(config=None):
     if config:
@@ -56,24 +50,13 @@ def get_config(config=None):
 
     dyndns = conf.get_config_dict(base_level, key_mangling=('-', '_'), get_first_key=True)
 
-    # We have gathered the dict representation of the CLI, but there are default
-    # options which we need to update into the dictionary retrived.
-    for interface in dyndns['interface']:
-        if 'service' in dyndns['interface'][interface]:
-            # 'Autodetect' protocol used by DynDNS service
-            for service in dyndns['interface'][interface]['service']:
-                if service in default_service_protocol:
-                    dyndns['interface'][interface]['service'][service].update(
-                        {'protocol' : default_service_protocol.get(service)})
-                else:
-                    dyndns['interface'][interface]['service'][service].update(
-                        {'custom': ''})
-
-        if 'rfc2136' in dyndns['interface'][interface]:
-            default_values = defaults(base_level + ['interface', 'rfc2136'])
-            for rfc2136 in dyndns['interface'][interface]['rfc2136']:
-                dyndns['interface'][interface]['rfc2136'][rfc2136] = dict_merge(
-                    default_values, dyndns['interface'][interface]['rfc2136'][rfc2136])
+    for address in dyndns['address']:
+        # Apply service specific defaults (stype = ['rfc2136', 'service'])
+        for svc_type in dyndns['address'][address]:
+            default_values = defaults(base_level + ['address', svc_type])
+            for svc_cfg in dyndns['address'][address][svc_type]:
+                dyndns['address'][address][svc_type][svc_cfg] = dict_merge(
+                    default_values, dyndns['address'][address][svc_type][svc_cfg])
 
     return dyndns
 
@@ -82,48 +65,37 @@ def verify(dyndns):
     if not dyndns:
         return None
 
-    # A 'node' corresponds to an interface
-    if 'interface' not in dyndns:
-        return None
-
-    for interface in dyndns['interface']:
+    for address in dyndns['address']:
         # RFC2136 - configuration validation
-        if 'rfc2136' in dyndns['interface'][interface]:
-            for rfc2136, config in dyndns['interface'][interface]['rfc2136'].items():
-
-                for tmp in ['record', 'zone', 'server', 'key']:
-                    if tmp not in config:
-                        raise ConfigError(f'"{tmp}" required for rfc2136 based '
-                                          f'DynDNS service on "{interface}"')
-
-                if not os.path.isfile(config['key']):
-                    raise ConfigError(f'"key"-file not found for rfc2136 based '
-                                      f'DynDNS service on "{interface}"')
-
-        # DynDNS service provider - configuration validation
-        if 'service' in dyndns['interface'][interface]:
-            for service, config in dyndns['interface'][interface]['service'].items():
-                error_msg = f'required for DynDNS service "{service}" on "{interface}"'
-                if 'host_name' not in config:
-                    raise ConfigError(f'"host-name" {error_msg}')
-
-                if 'login' not in config:
-                    if service != 'cloudflare' and ('protocol' not in config or config['protocol'] != 'cloudflare'):
-                        raise ConfigError(f'"login" (username) {error_msg}, unless using CloudFlare')
-
-                if 'password' not in config:
-                    raise ConfigError(f'"password" {error_msg}')
-
-                if 'zone' in config:
-                    if service != 'cloudflare' and ('protocol' not in config or config['protocol'] != 'cloudflare'):
-                        raise ConfigError(f'"zone" option only supported with CloudFlare')
-
-                if 'custom' in config:
-                    if 'protocol' not in config:
-                        raise ConfigError(f'"protocol" {error_msg}')
-
-                    if 'server' not in config:
-                        raise ConfigError(f'"server" {error_msg}')
+        if 'rfc2136' in dyndns['address'][address]:
+            for config in dyndns['address'][address]['rfc2136'].values():
+                for field in ['host_name', 'zone', 'server', 'key']:
+                    if field not in config:
+                        raise ConfigError(f'"{field.replace("_", "-")}" is required for RFC2136 '
+                                          f'based Dynamic DNS service on "{address}"')
+
+        # Dynamic DNS service provider - configuration validation
+        if 'service' in dyndns['address'][address]:
+            for service, config in dyndns['address'][address]['service'].items():
+                error_msg = f'is required for Dynamic DNS service "{service}" on "{address}"'
+
+                for field in ['host_name', 'password', 'protocol']:
+                    if field not in config:
+                        raise ConfigError(f'"{field.replace("_", "-")}" {error_msg}')
+
+                if config['protocol'] in zone_allowed and 'zone' not in config:
+                        raise ConfigError(f'"zone" {error_msg}')
+
+                if config['protocol'] not in zone_allowed and 'zone' in config:
+                        raise ConfigError(f'"{config["protocol"]}" does not support "zone"')
+
+                if config['protocol'] not in username_unnecessary:
+                    if 'username' not in config:
+                        raise ConfigError(f'"username" {error_msg}')
+
+                if (config['protocol'] not in dualstack_supported
+                        and config['ip_version'] == 'both'):
+                    raise ConfigError(f'"{config["protocol"]}" does not support IPv4 and IPv6 at the same time')
 
     return None