def handle_request(self, query: Packet, answer: Packet):
b_hwaddr = query.chaddr
s_hwaddr = self.fmt_hwaddr(b_hwaddr, query.hlen)
b_ipaddr = query.opts.get(dhcplib.DHCPOPT_IPADDR)
lease, offer = self.leases.pop(s_hwaddr, None), self.offers.pop(s_hwaddr, None)
if offer:
b_ipaddr, options = offer
else:
if b_ipaddr is None:
b_ipaddr = self.allocate(s_hwaddr)
elif self.get_ip_hwaddr(self.offers, b_ipaddr):
b_ipaddr = self.allocate(s_hwaddr)
elif self.get_ip_hwaddr(self.leases, b_ipaddr):
b_ipaddr = self.allocate(s_hwaddr)
elif not self.addr_in_network(b_ipaddr):
b_ipaddr = self.allocate(s_hwaddr)
options = self.get_options(s_hwaddr, query)
self.leases[s_hwaddr] = (b_ipaddr, options)
answer.opts[dhcplib.DHCPOPT_MSG_TYPE] = struct.pack('!B', dhcplib.DHCPACK)
answer.yiaddr = b_ipaddr
for (k, v) in options.items():
answer.opts[k] = v
self.finalize(s_hwaddr, query, answer)
def handle(self, interface, query: Packet):
answer = query.reply()
for middleware in self.middleware:
if middleware[0].handle_dhcp_packet(interface, query, answer):
return answer, middleware[0]
return answer, None
def read(self):
buf, ancdata, _, addr = self._sock.recvmsg(512, socket.CMSG_SPACE(100))
interface = self._get_cmsg_to(ancdata)
try:
query = Packet.parse(buf)
answer, pool = self._handler.handle(interface, query)
if not pool:
return
if answer.is_broadcast():
print('dhcp: got net broadcast on %s', interface)
self.broadcast(answer, interface, addr[1])
elif addr[0] == '0.0.0.0':
print('dhcp: got adr broadcast on %s', interface)
addr = (socket.inet_ntoa(pool.broadcast), addr[1])
self._queue.append((addr, answer))
else:
print('dhcp: got unicast from %s', addr[0])
self._queue.append((addr, answer))
except Exception as e:
traceback.print_exc()
