invirt-dhcpserver

   1 #!/usr/bin/python
   2 import sys
   3 import pydhcplib
   4 import pydhcplib.dhcp_network
   5 from pydhcplib.dhcp_packet import *
   6 from pydhcplib.type_hw_addr import hwmac
   7 from pydhcplib.type_ipv4 import ipv4
   8 from pydhcplib.type_strlist import strlist
   9 import socket
  10 import IN
  11
  12 import syslog as s
  13
  14 import time
  15 from invirt import database
  16 from invirt.config import structs as config
  17
  18 dhcp_options = {'subnet_mask': config.dhcp.netmask,
  19                 'router': config.dhcp.gateway,
  20                 'domain_name_server': ','.join(config.dhcp.dns),
  21                 'ip_address_lease_time': 60*60*24}
  22
  23 class DhcpBackend:
  24     def __init__(self):
  25         database.connect()
  26     def findNIC(self, mac):
  27         database.clear_cache()
  28         return database.NIC.query().filter_by(mac_addr=mac).first()
  29     def find_interface(self, packet):
  30         chaddr = hwmac(packet.GetHardwareAddress())
  31         nic = self.findNIC(str(chaddr))
  32         if nic is None or nic.ip is None:
  33             return None
  34         ipstr = ''.join(reversed(['%02X' % i for i in ipv4(nic.ip).list()]))
  35         for line in open('/proc/net/route'):
  36             parts = line.split()
  37             if parts[1] == ipstr:
  38                 s.syslog(s.LOG_DEBUG, "find_interface found "+str(nic.ip)+" on "+parts[0])
  39                 return parts[0]
  40         return None
  41
  42     def getParameters(self, **extra):
  43         all_options=dict(dhcp_options)
  44         all_options.update(extra)
  45         options = {}
  46         for parameter, value in all_options.iteritems():
  47             if value is None:
  48                 continue
  49             option_type = DhcpOptionsTypes[DhcpOptions[parameter]]
  50
  51             if option_type == "ipv4" :
  52                 # this is a single ip address
  53                 options[parameter] = map(int,value.split("."))
  54             elif option_type == "ipv4+" :
  55                 # this is multiple ip address
  56                 iplist = value.split(",")
  57                 opt = []
  58                 for single in iplist :
  59                     opt.extend(ipv4(single).list())
  60                 options[parameter] = opt
  61             elif option_type == "32-bits" :
  62                 # This is probably a number...
  63                 digit = int(value)
  64                 options[parameter] = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF]
  65             elif option_type == "16-bits" :
  66                 digit = int(value)
  67                 options[parameter] = [(digit>>8)&0xFF,digit&0xFF]
  68
  69             elif option_type == "char" :
  70                 digit = int(value)
  71                 options[parameter] = [digit&0xFF]
  72
  73             elif option_type == "bool" :
  74                 if value=="False" or value=="false" or value==0 :
  75                     options[parameter] = [0]
  76                 else : options[parameter] = [1]
  77
  78             elif option_type == "string" :
  79                 options[parameter] = strlist(value).list()
  80
  81             elif option_type == "RFC3397" :
  82                 parsed_value = ""
  83                 for item in value:
  84                     components = item.split('.')
  85                     item_fmt = "".join(chr(len(elt)) + elt for elt in components) + "\x00"
  86                     parsed_value += item_fmt
  87
  88                 options[parameter] = strlist(parsed_value).list()
  89
  90             else :
  91                 options[parameter] = strlist(value).list()
  92         return options
  93
  94     def Discover(self, packet):
  95         s.syslog(s.LOG_DEBUG, "dhcp_backend : Discover ")
  96         chaddr = hwmac(packet.GetHardwareAddress())
  97         nic = self.findNIC(str(chaddr))
  98         if nic is None or nic.machine is None:
  99             return False
 100         ip = nic.ip
 101         if ip is None:  #Deactivated?
 102             return False
 103
 104         options = {}
 105         if nic.hostname and '.' in nic.hostname:
 106             options['host_name'], options['domain_name'] = nic.hostname.split('.', 1)
 107         elif nic.machine.name:
 108             options['host_name'] = nic.machine.name
 109             options['domain_name'] = config.dns.domains[0]
 110         else:
 111             hostname = None
 112         if DhcpOptions['domain_search'] in packet.GetOption('parameter_request_list'):
 113             options['host_name'] += '.' + options['domain_name']
 114             del options['domain_name']
 115             options['domain_search'] = [config.dhcp.search_domain]
 116         if ip is not None:
 117             ip = ipv4(ip)
 118             s.syslog(s.LOG_DEBUG,"dhcp_backend : Discover result = "+str(ip))
 119             packet_parameters = self.getParameters(**options)
 120
 121             # FIXME: Other offer parameters go here
 122             packet_parameters["yiaddr"] = ip.list()
 123
 124             packet.SetMultipleOptions(packet_parameters)
 125             return True
 126         return False
 127
 128     def Request(self, packet):
 129         s.syslog(s.LOG_DEBUG, "dhcp_backend : Request")
 130
 131         discover = self.Discover(packet)
 132
 133         chaddr = hwmac(packet.GetHardwareAddress())
 134         request = packet.GetOption("request_ip_address")
 135         if not request:
 136             request = packet.GetOption("ciaddr")
 137         yiaddr = packet.GetOption("yiaddr")
 138
 139         if not discover:
 140             s.syslog(s.LOG_INFO,"Unknown MAC address: "+str(chaddr))
 141             return False
 142
 143         if yiaddr!="0.0.0.0" and yiaddr == request :
 144             s.syslog(s.LOG_INFO,"Ack ip "+str(yiaddr)+" for "+str(chaddr))
 145             return True
 146         else:
 147             s.syslog(s.LOG_INFO,"Requested ip "+str(request)+" not available for "+str(chaddr))
 148         return False
 149
 150     def Decline(self, packet):
 151         pass
 152     def Release(self, packet):
 153         pass
 154
 155
 156 class DhcpServer(pydhcplib.dhcp_network.DhcpServer):
 157     def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}):
 158         pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],)
 159         self.backend = backend
 160         s.syslog(s.LOG_DEBUG, "__init__ DhcpServer")
 161
 162     def SendDhcpPacketTo(self, To, packet):
 163         intf = self.backend.find_interface(packet)
 164         if intf:
 165             self.dhcp_socket.setsockopt(socket.SOL_SOCKET, IN.SO_BINDTODEVICE, intf)
 166             ret = self.dhcp_socket.sendto(packet.EncodePacket(), (To,self.emit_port))
 167             self.dhcp_socket.setsockopt(socket.SOL_SOCKET, IN.SO_BINDTODEVICE, '')
 168             return ret
 169         else:
 170             return self.dhcp_socket.sendto(packet.EncodePacket(),(To,self.emit_port))
 171
 172     def SendPacket(self, packet):
 173         """Encode and send the packet."""
 174
 175         giaddr = packet.GetOption('giaddr')
 176
 177         # in all case, if giaddr is set, send packet to relay_agent
 178         # network address defines by giaddr
 179         if giaddr!=[0,0,0,0] :
 180             agent_ip = ".".join(map(str,giaddr))
 181             self.SendDhcpPacketTo(agent_ip,packet)
 182             s.syslog(s.LOG_DEBUG, "SendPacket to agent : "+agent_ip)
 183
 184         # FIXME: This shouldn't broadcast if it has an IP address to send
 185         # it to instead. See RFC2131 part 4.1 for full details
 186         else :
 187             s.syslog(s.LOG_DEBUG, "No agent, broadcast packet.")
 188             self.SendDhcpPacketTo("255.255.255.255",packet)
 189
 190
 191     def HandleDhcpDiscover(self, packet):
 192         """Build and send DHCPOFFER packet in response to DHCPDISCOVER
 193         packet."""
 194
 195         logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str()
 196
 197         s.syslog(s.LOG_INFO, logmsg)
 198         offer = DhcpPacket()
 199         offer.CreateDhcpOfferPacketFrom(packet)
 200
 201         if self.backend.Discover(offer):
 202             self.SendPacket(offer)
 203         # FIXME : what if false ?
 204
 205
 206     def HandleDhcpRequest(self, packet):
 207         """Build and send DHCPACK or DHCPNACK packet in response to
 208         DHCPREQUEST packet. 4 types of DHCPREQUEST exists."""
 209
 210         ip = packet.GetOption("request_ip_address")
 211         sid = packet.GetOption("server_identifier")
 212         ciaddr = packet.GetOption("ciaddr")
 213         #packet.PrintHeaders()
 214         #packet.PrintOptions()
 215
 216         if sid != [0,0,0,0] and ciaddr == [0,0,0,0] :
 217             s.syslog(s.LOG_INFO, "Get DHCPREQUEST_SELECTING_STATE packet")
 218
 219         elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip :
 220             s.syslog(s.LOG_INFO, "Get DHCPREQUEST_INITREBOOT_STATE packet")
 221
 222         elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip :
 223             s.syslog(s.LOG_INFO,"Get DHCPREQUEST_INITREBOOT_STATE packet")
 224
 225         else : s.syslog(s.LOG_INFO,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented")
 226
 227         if self.backend.Request(packet):
 228             packet.TransformToDhcpAckPacket()
 229             self.SendPacket(packet)
 230         elif self.backend.Discover(packet):
 231             packet.TransformToDhcpNackPacket()
 232             self.SendPacket(packet)
 233         else:
 234             pass # We aren't authoritative, so don't reply if we don't know them.
 235
 236     # FIXME: These are not yet implemented.
 237     def HandleDhcpDecline(self, packet):
 238         s.syslog(s.LOG_INFO, "Get DHCPDECLINE packet")
 239         self.backend.Decline(packet)
 240
 241     def HandleDhcpRelease(self, packet):
 242         s.syslog(s.LOG_INFO,"Get DHCPRELEASE packet")
 243         self.backend.Release(packet)
 244
 245     def HandleDhcpInform(self, packet):
 246         s.syslog(s.LOG_INFO, "Get DHCPINFORM packet")
 247
 248         if self.backend.Request(packet) :
 249             packet.TransformToDhcpAckPacket()
 250             # FIXME : Remove lease_time from options
 251             self.SendPacket(packet)
 252
 253         # FIXME : what if false ?
 254
 255 if '__main__' == __name__:
 256     options = { "server_listen_port":67,
 257                 "client_listen_port":68,
 258                 "listen_address":"0.0.0.0"}
 259
 260     myip = socket.gethostbyname(socket.gethostname())
 261     if not myip:
 262         print "invirt-dhcpserver: cannot determine local IP address by looking up %s" % socket.gethostname()
 263         sys.exit(1)
 264
 265     dhcp_options['server_identifier'] = myip
 266
 267     backend = DhcpBackend()
 268     server = DhcpServer(backend, options)
 269
 270     while True : server.GetNextDhcpPacket()