dhcpserver.py

   1 #!/usr/bin/python
   2 import sys
   3 sys.path.append('pydhcplib/')
   4 import pydhcplib
   5 import pydhcplib.dhcp_network
   6 from pydhcplib.dhcp_packet import *
   7 from pydhcplib.type_hw_addr import hwmac
   8 from pydhcplib.type_ipv4 import ipv4
   9 from pydhcplib.type_strlist import strlist
  10
  11 import event_logger
  12 if '__main__' == __name__:
  13     event_logger.init("stdout", 'DEBUG', {})
  14 from event_logger import Log
  15
  16 import sipb_xen_database
  17
  18 dhcp_options = {'subnet_mask': '255.255.0.0',
  19                 'router': '18.181.0.1',
  20                 'domain_name_server': '18.70.0.160,18.71.0.151,18.72.0.3',
  21                 'domain_name': 'mit.edu'}
  22
  23
  24 class DhcpBackend:
  25     def __init__(self, database=None):
  26         if database is not None:
  27             sipb_xen_database.connect(database)
  28     def findIP(self, mac):
  29         value = sipb_xen_database.NIC.get_by(mac_addr=mac)
  30         if value is None:
  31             return None
  32         ip = value.ip
  33         if ip is None:  #Deactivated?
  34             return None
  35         return ip
  36     def getParameters(self):
  37         options = {}
  38         for parameter, value in dhcp_options.iteritems():
  39             option_type = DhcpOptionsTypes[DhcpOptions[parameter]]
  40
  41             if option_type == "ipv4" :
  42                 # this is a single ip address
  43                 options[parameter] = map(int,value.split("."))
  44             elif option_type == "ipv4+" :
  45                 # this is multiple ip address
  46                 iplist = value.split(",")
  47                 opt = []
  48                 for single in iplist :
  49                     opt.append(ipv4(single).list())
  50                 options[parameter] = opt
  51             elif option_type == "32-bits" :
  52                 # This is probably a number...
  53                 digit = int(value)
  54                 options[parameter] = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF]
  55             elif option_type == "16-bits" :
  56                 digit = int(value)
  57                 options[parameter] = [(digit>>8)&0xFF,digit&0xFF]
  58
  59             elif option_type == "char" :
  60                 digit = int(value)
  61                 options[parameter] = [digit&0xFF]
  62
  63             elif option_type == "bool" :
  64                 if value=="False" or value=="false" or value==0 :
  65                     options[parameter] = [0]
  66                 else : options[parameter] = [1]
  67
  68             elif option_type == "string" :
  69                 options[parameter] = strlist(value).list()
  70
  71             else :
  72                 options[parameter] = strlist(value).list()
  73         return options
  74
  75     def Discover(self, packet):
  76         Log.Output(Log.debug,"dhcp_backend : Discover ")
  77         chaddr = hwmac(packet.GetHardwareAddress())
  78         ip = self.findIP(str(chaddr))
  79         if ip is not None:
  80             ip = ipv4(ip)
  81             Log.Output(Log.debug,"dhcp_backend : Discover result = "+str(ip))
  82             packet_parameters = self.getParameters()
  83
  84             # FIXME: Other offer parameters go here
  85             packet_parameters["yiaddr"] = ip.list()
  86
  87             packet.SetMultipleOptions(packet_parameters)
  88             return True
  89         return False
  90
  91     def Request(self, packet):
  92         Log.Output(Log.debug, "dhcp_backend : Request")
  93
  94         discover = self.Discover(packet)
  95
  96         chaddr = hwmac(packet.GetHardwareAddress())
  97         request = packet.GetOption("request_ip_address")
  98         yiaddr = packet.GetOption("yiaddr")
  99
 100         if not discover:
 101             Log.Output(Log.info,"Unknown MAC address: "+str(chaddr))
 102             return False
 103
 104         if yiaddr!="0.0.0.0" and yiaddr == request :
 105             Log.Output(Log.info,"Ack ip "+str(yiaddr)+" for "+str(chaddr))
 106             return True
 107         else:
 108             Log.Output(Log.info,"Requested ip "+str(request)+" not available for "+str(chaddr))
 109         return False
 110
 111     def Decline(self, packet):
 112         pass
 113     def Release(self, packet):
 114         pass
 115
 116
 117 class DhcpServer(pydhcplib.dhcp_network.DhcpServer):
 118     def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}):
 119         pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],)
 120         self.backend = backend
 121         Log.Output(Log.debug, "__init__ DhcpServer")
 122
 123     def SendPacket(self, packet):
 124         """Encode and send the packet."""
 125
 126         giaddr = packet.GetOption('giaddr')
 127
 128         # in all case, if giaddr is set, send packet to relay_agent
 129         # network address defines by giaddr
 130         if giaddr!=[0,0,0,0] :
 131             agent_ip = ".".join(map(str,giaddr))
 132             self.SendDhcpPacketTo(agent_ip,packet)
 133             Log.Output(Log.debug, "SendPacket to agent : "+agent_ip)
 134
 135         # FIXME: This shouldn't broadcast if it has an IP address to send
 136         # it to instead. See RFC2131 part 4.1 for full details
 137         else :
 138             Log.Output(Log.debug, "No agent, broadcast packet.")
 139             self.SendDhcpPacketTo("255.255.255.255",packet)
 140
 141
 142     def HandleDhcpDiscover(self, packet):
 143         """Build and send DHCPOFFER packet in response to DHCPDISCOVER
 144         packet."""
 145
 146         logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str()
 147
 148         Log.Output(Log.info, logmsg)
 149         offer = DhcpPacket()
 150         offer.CreateDhcpOfferPacketFrom(packet)
 151
 152         if self.backend.Discover(offer):
 153             self.SendPacket(offer)
 154         # FIXME : what if false ?
 155
 156
 157     def HandleDhcpRequest(self, packet):
 158         """Build and send DHCPACK or DHCPNACK packet in response to
 159         DHCPREQUEST packet. 4 types of DHCPREQUEST exists."""
 160
 161         ip = packet.GetOption("request_ip_address")
 162         sid = packet.GetOption("server_identifier")
 163         ciaddr = packet.GetOption("ciaddr")
 164
 165         if sid != [0,0,0,0] and ciaddr == [0,0,0,0] :
 166             Log.Output(Log.info, "Get DHCPREQUEST_SELECTING_STATE packet")
 167
 168         elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip :
 169             Log.Output(Log.info, "Get DHCPREQUEST_INITREBOOT_STATE packet")
 170
 171         elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip :
 172             Log.Output(Log.info,"Get DHCPREQUEST_INITREBOOT_STATE packet")
 173
 174         else : Log.Output(Log.info,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented")
 175
 176         if self.backend.Request(packet) : packet.TransformToDhcpAckPacket()
 177         else : packet.TransformToDhcpNackPacket()
 178
 179         self.SendPacket(packet)
 180
 181
 182
 183     # FIXME: These are not yet implemented.
 184     def HandleDhcpDecline(self, packet):
 185         Log.Output(Log.info, "Get DHCPDECLINE packet")
 186         self.backend.Decline(packet)
 187
 188     def HandleDhcpRelease(self, packet):
 189         Log.Output(Log.info,"Get DHCPRELEASE packet")
 190         self.backend.Release(packet)
 191
 192     def HandleDhcpInform(self, packet):
 193         Log.Output(Log.info, "Get DHCPINFORM packet")
 194
 195         if self.backend.Request(packet) :
 196             packet.TransformToDhcpAckPacket()
 197             # FIXME : Remove lease_time from options
 198             self.SendPacket(packet)
 199
 200         # FIXME : what if false ?
 201
 202 if '__main__' == __name__:
 203     options = { "server_listen_port":67,
 204                 "client_listen_port":68,
 205                 "listen_address":"0.0.0.0"}
 206     backend = DhcpBackend('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
 207     server = DhcpServer(backend, options)
 208
 209     while True : server.GetNextDhcpPacket()