unbound+DHCP: Read correct DHCP domain name for lease

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

config/unbound/unbound-dhcp-leases-bridge

@@ -22,6 +22,7 @@
 import argparse
 import datetime
 import daemon
+import ipaddress
 import logging
 import logging.handlers
 import re
@@ -220,7 +221,47 @@ class Lease(object):
 
 	@property
 	def domain(self):
-		return "local" # XXX
+		# Load ethernet settings
+		ethernet_settings = self.read_settings("/var/ipfire/ethernet/settings")
+
+		# Load DHCP settings
+		dhcp_settings = self.read_settings("/var/ipfire/dhcp/settings")
+
+		subnets = {}
+		for zone in ("GREEN", "BLUE"):
+			if not dhcp_settings.get("ENABLE_%s" % zone) == "on":
+				continue
+
+			netaddr = ethernet_settings.get("%s_NETADDRESS" % zone)
+			submask = ethernet_settings.get("%s_NETMASK" % zone)
+
+			subnet = ipaddress.ip_network("%s/%s" % (netaddr, submask))
+			domain = dhcp_settings.get("DOMAIN_NAME_%s" % zone)
+
+			subnets[subnet] = domain
+
+		address = ipaddress.ip_address(self.ipaddr)
+
+		for subnet, domain in subnets.items():
+			if address in subnet:
+				return domain
+
+		# Fall back to localdomain if no match could be found
+		return "localdomain"
+
+	@staticmethod
+	def read_settings(filename):
+		settings = {}
+
+		with open(filename) as f:
+			for line in f.readlines():
+				# Remove line-breaks
+				line = line.rstrip()
+
+				k, v = line.split("=", 1)
+				settings[k] = v
+
+		return settings
 
 	@property
 	def fqdn(self):