dhcpserver.py

   1 #!/usr/bin/python
   2 import sys.path
   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
  10 import event_logger
  11 if '__main__' == __name__:
  12     event_logger.init("stdout", 'INFO', {})
  13 from event_logger import Log
  14
  15 import sipb_xen_database
  16
  17 class DhcpBackend:
  18     def __init__(self, database=None):
  19         if database is not None:
  20             sipb_xen_database.connect(database)
  21     def findIP(self, mac):
  22         value = sipb_xen_database.NIC.get_by(mac_addr=mac)
  23         if value is None:
  24             return None
  25         ip = value.ip
  26         if ip is None:  #Deactivated?
  27             return None
  28         return ip
  29
  30     def Discover(self, packet):
  31         Log.Output(Log.debug,"dhcp_backend : Discover ")
  32         chaddr = hwmac(packet.GetHardwareAddress())
  33         ip = self.findIP(str(chaddr))
  34         if ip is not None:
  35             ip = ipv4(ip)
  36             Log.Output(Log.debug,"dhcp_backend : Discover result = "+str(ip))
  37             packet_parameters = {}
  38
  39             # FIXME: Other offer parameters go here
  40             packet_parameters["yiaddr"] = ip.list()
  41
  42             packet.SetMultipleOptions(packet_parameters)
  43             return True
  44         return False
  45
  46     def Request(self, packet):
  47         Log.Output(Log.debug, "dhcp_backend : Request")
  48
  49         discover = self.Discover(packet)
  50
  51         chaddr = hwmac(packet.GetHardwareAddress())
  52         request = packet.GetOption("request_ip_address")
  53         yiaddr = packet.GetOption("yiaddr")
  54
  55         if not discover:
  56             Log.Output(Log.info,"Unknown MAC address: "+str(chaddr))
  57             return False
  58
  59         if yiaddr!="0.0.0.0" and yiaddr == request :
  60             Log.Output(Log.info,"Ack ip "+str(yiaddr)+" for "+str(chaddr))
  61             return True
  62         else:
  63             Log.Output(Log.info,"Requested ip "+str(request)+" not available for "+str(chaddr))
  64         return False
  65
  66     def Decline(self, packet):
  67         pass
  68     def Release(self, packet):
  69         pass
  70
  71
  72 class DhcpServer(pydhcplib.dhcp_network.DhcpServer):
  73     def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}):
  74         pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],)
  75         self.backend = backend
  76         Log.Output(Log.debug, "__init__ DhcpServer")
  77
  78     def SendPacket(self, packet):
  79         """Encode and send the packet."""
  80
  81         giaddr = packet.GetOption('giaddr')
  82
  83         # in all case, if giaddr is set, send packet to relay_agent
  84         # network address defines by giaddr
  85         if giaddr!=[0,0,0,0] :
  86             agent_ip = ".".join(map(str,giaddr))
  87             self.SendDhcpPacketTo(agent_ip,packet)
  88             Log.Output(Log.debug, "SendPacket to agent : "+agent_ip)
  89
  90         # FIXME: This shouldn't broadcast if it has an IP address to send
  91         # it to instead. See RFC2131 part 4.1 for full details
  92         else :
  93             Log.Output(Log.debug, "No agent, broadcast packet.")
  94             self.SendDhcpPacketTo("255.255.255.255",packet)
  95
  96
  97     def HandleDhcpDiscover(self, packet):
  98         """Build and send DHCPOFFER packet in response to DHCPDISCOVER
  99         packet."""
 100
 101         logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str()
 102
 103         Log.Output(Log.info, logmsg)
 104         offer = DhcpPacket()
 105         offer.CreateDhcpOfferPacketFrom(packet)
 106
 107         if self.backend.Discover(offer) :
 108             self.SendPacket(offer)
 109         # FIXME : what if false ?
 110
 111
 112     def HandleDhcpRequest(self, packet):
 113         """Build and send DHCPACK or DHCPNACK packet in response to
 114         DHCPREQUEST packet. 4 types of DHCPREQUEST exists."""
 115
 116         ip = packet.GetOption("request_ip_address")
 117         sid = packet.GetOption("server_identifier")
 118         ciaddr = packet.GetOption("ciaddr")
 119
 120         if sid != [0,0,0,0] and ciaddr == [0,0,0,0] :
 121             Log.Output(Log.info, "Get DHCPREQUEST_SELECTING_STATE packet")
 122
 123         elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip :
 124             Log.Output(Log.info, "Get DHCPREQUEST_INITREBOOT_STATE packet")
 125
 126         elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip :
 127             Log.Output(Log.info,"Get DHCPREQUEST_INITREBOOT_STATE packet")
 128
 129         else : Log.Output(Log.info,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented")
 130
 131         if self.backend.Request(packet) : packet.TransformToDhcpAckPacket()
 132         else : packet.TransformToDhcpNackPacket()
 133
 134         self.SendPacket(packet)
 135
 136
 137
 138     # FIXME: These are not yet implemented.
 139     def HandleDhcpDecline(self, packet):
 140         Log.Output(Log.info, "Get DHCPDECLINE packet")
 141         self.backend.Decline(packet)
 142
 143     def HandleDhcpRelease(self, packet):
 144         Log.Output(Log.info,"Get DHCPRELEASE packet")
 145         self.backend.Release(packet)
 146
 147     def HandleDhcpInform(self, packet):
 148         Log.Output(Log.info, "Get DHCPINFORM packet")
 149
 150         if self.backend.Request(packet) :
 151             packet.TransformToDhcpAckPacket()
 152             # FIXME : Remove lease_time from options
 153             self.SendPacket(packet)
 154
 155         # FIXME : what if false ?
 156
 157 if '__main__' == __name__:
 158     options = { "server_listen_port":67,
 159                 "client_listen_port":68,
 160                 "listen_address":"0.0.0.0"}
 161     backend = DhcpBackend('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
 162     server = DhcpServer(backend, options)
 163
 164     while True : server.GetNextDhcpPacket()