add busybox udhcps functionality

VMdhcpd.py

@@ -0,0 +1,69 @@
+import os, sys
+from string import Template
+from subprocess import PIPE, Popen,call
+
+BUSYBOX_BINARY = "busybox"
+TEMPLATE_FILE = os.path.dirname(os.path.realpath(__file__)) + "/udhcpd.conf.template"
+
+class VMdhcpd:
+	def __init__(self, vmid ,config):
+		self.__config = config
+		self.__vmid = vmid
+
+	def start(self):
+		self.__kill()
+
+		if ('VMs' in self.__config) and (self.__vmid in self.__config['VMs']):
+			config = self.__config['VMs'][self.__vmid]
+		else:
+			raise Exception("No such VM configuration")
+
+		if "network" in config and "ip" in config["network"]:
+			config_file_str = None
+			with open(TEMPLATE_FILE) as f:
+				config_file_str = f.read()	
+			
+			template_params = {
+				"ip_address" : config['network']['ip'][0],
+				"interface" : config['network']['dev'],
+				"pidfile" : self.__config['dhcpd']['pidfile'].replace("$VMID", self.__vmid),
+				"router" : self.__config['dhcpd']['router'],
+				"dns1" : self.__config['dhcpd']['dns1'],
+				"dns2" : self.__config['dhcpd']['dns2']
+			}
+
+			config_file_str = Template(config_file_str).substitute(template_params)
+			
+			#imake sure the interface has some address as udhcpd can't use it without
+			call(["ip", "addr", "replace", "dev", config['network']['dev'], "192.168.123.221/32"], stdout=open("/dev/null"))
+
+			command = BUSYBOX_BINARY + " udhcpd -f - << EOFEOFEOF\n" + config_file_str + "\nEOFEOFEOF"
+			Popen(command, stdout=open("/dev/null"), stderr=open("/dev/null"), shell=True, start_new_session=True)
+			#os.system(command)
+
+
+	def stop(self):
+		self.__kill()
+
+	def __kill(self):
+		pid,filename = self.getPid()
+		if(pid is not None):
+			os.kill(pid,9)
+
+		try:
+			os.remove(filename)
+		except OSError:
+			pass
+
+	def getPid(self) -> "(int or None, filname)":
+		result = None
+		filename = self.__config['dhcpd']['pidfile'].replace("$VMID", self.__vmid)
+		try:
+			with open(filename) as pidfd:
+				firstline = pidfd.readline().strip()
+				result = int(firstline) if firstline.isdigit() else None
+		except IOError:
+			pass
+		return (result,filename)
+	
+