def __init__(self, listen_interface, backends):
_DhcpServer.__init__(
self, \
DEFAULT_LISTEN_ADDRESS, \
DEFAULT_CLIENT_PORT, \
DEFAULT_SERVER_PORT \
)
self.BindToDevice(listen_interface)
self.backends = backends
self.ip_lease_manager = IPLeaseManager("lease.db")
self._socket = self.dhcp_socket
class DhcpServer(_DhcpServer):
_socket = None
def __init__(self, listen_interface, backends):
_DhcpServer.__init__(
self, \
DEFAULT_LISTEN_ADDRESS, \
DEFAULT_CLIENT_PORT, \
DEFAULT_SERVER_PORT \
)
self.BindToDevice(listen_interface)
self.backends = backends
self.ip_lease_manager = IPLeaseManager("lease.db")
self._socket = self.dhcp_socket
def _create_socket(self):
_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
_socket.setsockopt(socket.SOL_SOCKET,socket.SO_BROADCAST,1)
_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
_socket.bind((DEFAULT_LISTEN_ADDRESS, DEFAULT_SERVER_PORT))
self._socket = _socket
def recieve_next_dhcp_packet(self, timeout=30):
print "Here"
while True:
data = select.select([self._socket], [], [], timeout)[0]
if not len(data):
return None
packet_data, source_address = self._socket.recvfrom(2048)
if packet_data:
packet = DhcpPacket()
packet.source_address = source_address
packet.DecodePacket(packet_data)
return packet
def process_dhcp_packet(self, packet):
self.HandleDhcpAll(packet)
if packet.IsDhcpDiscoverPacket():
self.HandleDhcpDiscover(packet)
elif packet.IsDhcpRequestPacket():
self.HandleDhcpRequest(packet)
elif packet.IsDhcpDeclinePacket():
self.HandleDhcpDecline(packet)
elif packet.IsDhcpReleasePacket():
self.HandleDhcpRelease(packet)
elif packet.IsDhcpInformPacket():
self.HandleDhcpInform(packet)
elif packet.IsDhcpOfferPacket():
self.HandleDhcpOffer(packet)
elif packet.IsDhcpAckPacket():
self.HandleDhcpAck(packet)
elif packet.IsDhcpNackPacket():
self.HandleDhcpNack(packet)
else:
self.HandleDhcpUnknown(packet)
def process_next_dhcp_packet(self, timeout=30):
dhcp_packet = self.recieve_next_dhcp_packet(timeout)
self.process_dhcp_packet(dhcp_packet)
return dhcp_packet
def BindToDevice(self, device) :
self.dhcp_socket.setsockopt(socket.SOL_SOCKET,IN.SO_BINDTODEVICE,struct.pack("5s", device))
def _get_ipv4_range_collection(self, offer_options=dict()):
"""Returns an AddressRangeCollection"""
network = offer_options.pop("network", None)
subnet_mask = offer_options.get("subnet_mask", None)
network_prefix = offer_options.pop("network_prefix", None)
ip_ranges_str = offer_options.pop("ip_range", None)
if ip_ranges_str:
return parse_ipv4_range_collection(ip_ranges_str)
elif network:
raise NotImplementedError
elif subnet_mask and network_prefix:
raise NotImplementedError
raise Exception("Cannot determine network info for client. Missing prefix or subnet information")
def _calculate_entry_options(self, mac_str):
joined_offer_options = dict()
for backend in self.backends:
entry_options = backend.query_options(mac_str, joined_offer_options)
if not entry_options:
continue
joined_offer_options.update(entry_options)
return joined_offer_options
def _set_packet_options(self, packet, options):
for k, v in options.iteritems():
option_name, value = parse_dhcp_option(k, v)
packet.SetOption(option_name, value)
def _get_requested_ip_from_packet(self, packet):
for attr in ('ciaddr', 'request_ip_address'):
if sum(packet.GetOption(attr)):
requested_ip = IPv4.from_list(packet.GetOption(attr))
return requested_ip
return None
def HandleDhcpDiscover(self, packet):
mac = MAC.from_list(packet.GetHardwareAddress())
logging.debug("DISCOVER: %s", str(mac))
entry_options = self._calculate_entry_options(str(mac))
ipv4_range_collection = self._get_ipv4_range_collection(entry_options)
self._set_packet_options(packet, entry_options)
backend_ip = entry_options.get('yiaddr', None)
requested_ip = self._get_requested_ip_from_packet(packet)
ip = None
if backend_ip:
ip = IPv4.from_list(backend_ip)
self.ip_lease_manager.reallocate_ip_address(ip)
logging.debug("DISCOVER: %s gets static ip: %s", str(mac), str(ip))
else:
ip = self.ip_lease_manager.allocate_ip_address(ipv4_range_collection, mac, requested_ip=requested_ip)
logging.debug("DISCOVER: %s requested ip %s, giving %s", str(mac), str(requested_ip), str(ip))
packet.SetOption('yiaddr', list(ip))
packet.TransformToDhcpOfferPacket()
logging.debug("DISCOVER: Sent OFFER to %s", str(mac))
self.SendDhcpPacketTo(packet, "255.255.255.255", 68)
def HandleDhcpRequest(self, packet):
mac = MAC.from_list(packet.GetHardwareAddress())
request_ip = self._get_requested_ip_from_packet(packet) or \
IP.from_list(packet.GetOption('yiaddr'))
logging.debug("REQUEST: %s requested %s", str(mac), str(request_ip))
if sum(packet.GetOption('giaddr')):
dest_relay_or_gateway = str(IP.from_list(packet.GetOption('giaddr')))
else:
dest_relay_or_gateway = "255.255.255.255"
lease_time = 30000
entry_options = self._calculate_entry_options(str(mac))
ipv4_range_collection = self._get_ipv4_range_collection(entry_options)
try:
if not self.ip_lease_manager.was_last_leased_to(request_ip, mac):
logging.debug("REQUEST: ERROR: %s requested ip not leased to him: %s", str(mac), str(request_ip))
packet.TransformToDhcpNackPacket()
logging.debug("REQUEST: Sent DENY to %s", str(mac))
self.SendDhcpPacketTo(packet, dest_relay_or_gateway, 68)
return
self.ip_lease_manager.lease_ip_address(request_ip, mac, lease_time)
except LeaseError as e:
logging.debug("REQUEST: ERROR: ", str(e))
return
self._set_packet_options(packet, entry_options)
packet.SetOption('yiaddr', list(request_ip))
packet.TransformToDhcpAckPacket()
logging.debug("REQUEST: Sent ACK to %s", str(mac))
self.SendDhcpPacketTo(packet, dest_relay_or_gateway, 68)
def HandleDhcpDecline(self, packet):
mac = MAC.from_list(packet.GetHardwareAddress())
logging.debug("DECLINE: from %s", str(mac))
self.ip_lease_manager.delete_lease(mac=mac)
def HandleDhcpRelease(self, packet):
mac = MAC.from_list(packet.GetHardwareAddress())
logging.debug("RELEASE: from %s", str(mac))
self.ip_lease_manager.delete_lease(mac=mac)
def HandleDhcpInform(self, packet):
mac = MAC.from_list(packet.GetHardwareAddress())
logging.debug("GOT: INFORM from " + str(mac))
entry_options = self._calculate_entry_options(str(mac))
ipv4_range_collection = self._get_ipv4_range_collection(entry_options)
self._set_packet_options(packet, entry_options)
client_lease = self.ip_lease_manager.get_lease(mac=mac)
if not client_lease:
return None
ip = IPv4.from_str(client_lease.ip_str)
packet.SetOption('yiaddr', list(ip))
packet.TransformToDhcpAckPacket()
dest_relay_or_gateway = None
if sum(packet.GetOption('giaddr')):
dest_relay_or_gateway = str(IP.from_list(packet.GetOption('giaddr')))
else:
dest_relay_or_gateway = "255.255.255.255"
logging.debug("SENT: ACK")
self.SendDhcpPacketTo(packet, dest_relay_or_gateway, 68)
