Add support for odhcpd DHCP server (#9858)

This commit adds support for the odhcp DHCP server in addition to
dnsmasq. A new configuration option 'dhcp_software' has been added and
allows the user to set the server used (defaults to dnsmasq to not break
existing installations).

homeassistant/components/device_tracker/ubus.py

@@ -19,16 +19,29 @@ from homeassistant.exceptions import HomeAssistantError
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_DHCP_SOFTWARE = 'dhcp_software'
+DEFAULT_DHCP_SOFTWARE = 'dnsmasq'
+DHCP_SOFTWARES = [
+    'dnsmasq',
+    'odhcpd'
+]
+
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_HOST): cv.string,
     vol.Required(CONF_PASSWORD): cv.string,
-    vol.Required(CONF_USERNAME): cv.string
+    vol.Required(CONF_USERNAME): cv.string,
+    vol.Optional(CONF_DHCP_SOFTWARE,
+                 default=DEFAULT_DHCP_SOFTWARE): vol.In(DHCP_SOFTWARES)
 })
 
 
 def get_scanner(hass, config):
     """Validate the configuration and return an ubus scanner."""
-    scanner = UbusDeviceScanner(config[DOMAIN])
+    dhcp_sw = config[DOMAIN][CONF_DHCP_SOFTWARE]
+    if dhcp_sw == 'dnsmasq':
+        scanner = DnsmasqUbusDeviceScanner(config[DOMAIN])
+    else:
+        scanner = OdhcpdUbusDeviceScanner(config[DOMAIN])
 
     return scanner if scanner.success_init else None
 
@@ -70,7 +83,6 @@ class UbusDeviceScanner(DeviceScanner):
         self.session_id = _get_session_id(self.url, self.username,
                                           self.password)
         self.hostapd = []
-        self.leasefile = None
         self.mac2name = None
         self.success_init = self.session_id is not None
 
@@ -79,44 +91,29 @@ class UbusDeviceScanner(DeviceScanner):
         self._update_info()
         return self.last_results
 
+    def _generate_mac2name(self):
+        """Must be implemented depending on the software."""
+        raise NotImplementedError
+
     @_refresh_on_acccess_denied
     def get_device_name(self, mac):
         """Return the name of the given device or None if we don't know."""
-        if self.leasefile is None:
-            result = _req_json_rpc(
-                self.url, self.session_id, 'call', 'uci', 'get',
-                config="dhcp", type="dnsmasq")
-            if result:
-                values = result["values"].values()
-                self.leasefile = next(iter(values))["leasefile"]
-            else:
-                return
-
         if self.mac2name is None:
-            result = _req_json_rpc(
-                self.url, self.session_id, 'call', 'file', 'read',
-                path=self.leasefile)
-            if result:
-                self.mac2name = dict()
-                for line in result["data"].splitlines():
-                    hosts = line.split(" ")
-                    self.mac2name[hosts[1].upper()] = hosts[3]
-            else:
-                # Error, handled in the _req_json_rpc
-                return
-
-        return self.mac2name.get(mac.upper(), None)
+            self._generate_mac2name()
+        name = self.mac2name.get(mac.upper(), None)
+        self.mac2name = None
+        return name
 
     @_refresh_on_acccess_denied
     def _update_info(self):
-        """Ensure the information from the Luci router is up to date.
+        """Ensure the information from the router is up to date.
 
         Returns boolean if scanning successful.
         """
         if not self.success_init:
             return False
 
-        _LOGGER.info("Checking ARP")
+        _LOGGER.info("Checking hostapd")
 
         if not self.hostapd:
             hostapd = _req_json_rpc(
@@ -136,6 +133,57 @@ class UbusDeviceScanner(DeviceScanner):
         return bool(results)
 
 
+class DnsmasqUbusDeviceScanner(UbusDeviceScanner):
+    """Implement the Ubus device scanning for the dnsmasq DHCP server."""
+
+    def __init__(self, config):
+        """Initialize the scanner."""
+        super(DnsmasqUbusDeviceScanner, self).__init__(config)
+        self.leasefile = None
+
+    def _generate_mac2name(self):
+        if self.leasefile is None:
+            result = _req_json_rpc(
+                self.url, self.session_id, 'call', 'uci', 'get',
+                config="dhcp", type="dnsmasq")
+            if result:
+                values = result["values"].values()
+                self.leasefile = next(iter(values))["leasefile"]
+            else:
+                return
+
+        result = _req_json_rpc(
+            self.url, self.session_id, 'call', 'file', 'read',
+            path=self.leasefile)
+        if result:
+            self.mac2name = dict()
+            for line in result["data"].splitlines():
+                hosts = line.split(" ")
+                self.mac2name[hosts[1].upper()] = hosts[3]
+        else:
+            # Error, handled in the _req_json_rpc
+            return
+
+
+class OdhcpdUbusDeviceScanner(UbusDeviceScanner):
+    """Implement the Ubus device scanning for the odhcp DHCP server."""
+
+    def _generate_mac2name(self):
+        result = _req_json_rpc(
+            self.url, self.session_id, 'call', 'dhcp', 'ipv4leases')
+        if result:
+            self.mac2name = dict()
+            for device in result["device"].values():
+                for lease in device['leases']:
+                    mac = lease['mac']  # mac = aabbccddeeff
+                    # Convert it to expected format with colon
+                    mac = ":".join(mac[i:i+2] for i in range(0, len(mac), 2))
+                    self.mac2name[mac.upper()] = lease['hostname']
+        else:
+            # Error, handled in the _req_json_rpc
+            return
+
+
 def _req_json_rpc(url, session_id, rpcmethod, subsystem, method, **params):
     """Perform one JSON RPC operation."""
     data = json.dumps({"jsonrpc": "2.0",