Start using xvm.mit.edu for DHCP
[invirt/packages/invirt-dhcp.git] / code / dhcpserver.py
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 event_logger
13 if '__main__' == __name__:
14     event_logger.init("stdout", 'DEBUG', {})
15 from event_logger import Log
16
17 import psycopg2
18 import time
19 import sipb_xen_database
20 from sqlalchemy import create_engine
21
22 dhcp_options = {'subnet_mask': '255.255.0.0',
23                 'router': '18.181.0.1',
24                 'domain_name_server': '18.70.0.160,18.71.0.151,18.72.0.3',
25                 'ip_address_lease_time': 60*60*24}
26
27 class DhcpBackend:
28     def __init__(self, database=None):
29         if database is not None:
30             self.database = database
31             sipb_xen_database.connect(create_engine(database))
32     def findNIC(self, mac):
33         sipb_xen_database.clear_cache()
34         for i in range(3):
35             try:
36                 value = sipb_xen_database.NIC.get_by(mac_addr=mac)
37             except psycopg2.OperationalError:
38                 time.sleep(0.5)
39                 if i == 2:  #Try twice to reconnect.
40                     raise
41                 #Sigh.  SQLAlchemy should do this itself.
42                 sipb_xen_database.connect(create_engine(self.database))
43             else:
44                 break
45         return value
46     def find_interface(self, packet):
47         chaddr = hwmac(packet.GetHardwareAddress())
48         nic = self.findNIC(str(chaddr))
49         if nic is None or nic.ip is None:
50             return ("18.181.0.60", None)
51         ipstr = ''.join(reversed(['%02X' % i for i in ipv4(nic.ip).list()]))
52         for line in open('/proc/net/route'):
53             parts = line.split()
54             if parts[1] == ipstr:
55                 Log.Output(Log.debug, "find_interface found "+str(nic.ip)+" on "+parts[0])
56                 return ("18.181.0.60", parts[0])
57         return ("18.181.0.60", None)
58                             
59     def getParameters(self, **extra):
60         all_options=dict(dhcp_options)
61         all_options.update(extra)
62         options = {}
63         for parameter, value in all_options.iteritems():
64             if value is None:
65                 continue
66             option_type = DhcpOptionsTypes[DhcpOptions[parameter]]
67
68             if option_type == "ipv4" :
69                 # this is a single ip address
70                 options[parameter] = map(int,value.split("."))
71             elif option_type == "ipv4+" :
72                 # this is multiple ip address
73                 iplist = value.split(",")
74                 opt = []
75                 for single in iplist :
76                     opt.extend(ipv4(single).list())
77                 options[parameter] = opt
78             elif option_type == "32-bits" :
79                 # This is probably a number...
80                 digit = int(value)
81                 options[parameter] = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF]
82             elif option_type == "16-bits" :
83                 digit = int(value)
84                 options[parameter] = [(digit>>8)&0xFF,digit&0xFF]
85
86             elif option_type == "char" :
87                 digit = int(value)
88                 options[parameter] = [digit&0xFF]
89
90             elif option_type == "bool" :
91                 if value=="False" or value=="false" or value==0 :
92                     options[parameter] = [0]
93                 else : options[parameter] = [1]
94                     
95             elif option_type == "string" :
96                 options[parameter] = strlist(value).list()
97             
98             elif option_type == "RFC3397" :
99                 parsed_value = ""
100                 for item in value:
101                     components = item.split('.')
102                     item_fmt = "".join(chr(len(elt)) + elt for elt in components) + "\x00"
103                     parsed_value += item_fmt
104                 
105                 options[parameter] = strlist(parsed_value).list()
106             
107             else :
108                 options[parameter] = strlist(value).list()
109         return options
110
111     def Discover(self, packet):
112         Log.Output(Log.debug,"dhcp_backend : Discover ")
113         chaddr = hwmac(packet.GetHardwareAddress())
114         nic = self.findNIC(str(chaddr))
115         if nic is None or nic.machine is None:
116             return False
117         ip = nic.ip
118         if ip is None:  #Deactivated?
119             return False
120
121         options = {}
122         if nic.hostname and '.' in nic.hostname:
123             options['host_name'], options['domain_name'] = nic.hostname.split('.', 1)
124         elif nic.machine.name:
125             options['host_name'] = nic.machine.name
126             options['domain_name'] = 'xvm.mit.edu'
127         else:
128             hostname = None
129         if DhcpOptions['domain_search'] in packet.GetOption('parameter_request_list'):
130             options['host_name'] += '.' + options['domain_name']
131             del options['domain_name']
132             options['domain_search'] = ['mit.edu']
133         if ip is not None:
134             ip = ipv4(ip)
135             Log.Output(Log.debug,"dhcp_backend : Discover result = "+str(ip))
136             packet_parameters = self.getParameters(**options)
137
138             # FIXME: Other offer parameters go here
139             packet_parameters["yiaddr"] = ip.list()
140             
141             packet.SetMultipleOptions(packet_parameters)
142             return True
143         return False
144         
145     def Request(self, packet):
146         Log.Output(Log.debug, "dhcp_backend : Request")
147         
148         discover = self.Discover(packet)
149         
150         chaddr = hwmac(packet.GetHardwareAddress())
151         request = packet.GetOption("request_ip_address")
152         if not request:
153             request = packet.GetOption("ciaddr")
154         yiaddr = packet.GetOption("yiaddr")
155
156         if not discover:
157             Log.Output(Log.info,"Unknown MAC address: "+str(chaddr))
158             return False
159         
160         if yiaddr!="0.0.0.0" and yiaddr == request :
161             Log.Output(Log.info,"Ack ip "+str(yiaddr)+" for "+str(chaddr))
162             return True
163         else:
164             Log.Output(Log.info,"Requested ip "+str(request)+" not available for "+str(chaddr))
165         return False
166
167     def Decline(self, packet):
168         pass
169     def Release(self, packet):
170         pass
171     
172
173 class DhcpServer(pydhcplib.dhcp_network.DhcpServer):
174     def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}):
175         pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],)
176         self.backend = backend
177         Log.Output(Log.debug, "__init__ DhcpServer")
178
179     def SendDhcpPacketTo(self, To, packet):
180         (ip, intf) = self.backend.find_interface(packet)
181         if intf:
182             out_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
183             out_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST,1)
184             out_socket.setsockopt(socket.SOL_SOCKET, IN.SO_BINDTODEVICE, intf)
185             #out_socket.bind((ip, self.listen_port))
186             ret = out_socket.sendto(packet.EncodePacket(), (To,self.emit_port))
187             out_socket.close()
188             return ret
189         else:
190             return self.dhcp_socket.sendto(packet.EncodePacket(),(To,self.emit_port))
191
192     def SendPacket(self, packet):
193         """Encode and send the packet."""
194         
195         giaddr = packet.GetOption('giaddr')
196
197         # in all case, if giaddr is set, send packet to relay_agent
198         # network address defines by giaddr
199         if giaddr!=[0,0,0,0] :
200             agent_ip = ".".join(map(str,giaddr))
201             self.SendDhcpPacketTo(agent_ip,packet)
202             Log.Output(Log.debug, "SendPacket to agent : "+agent_ip)
203
204         # FIXME: This shouldn't broadcast if it has an IP address to send
205         # it to instead. See RFC2131 part 4.1 for full details
206         else :
207             Log.Output(Log.debug, "No agent, broadcast packet.")
208             self.SendDhcpPacketTo("255.255.255.255",packet)
209             
210
211     def HandleDhcpDiscover(self, packet):
212         """Build and send DHCPOFFER packet in response to DHCPDISCOVER
213         packet."""
214
215         logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str()
216
217         Log.Output(Log.info, logmsg)
218         offer = DhcpPacket()
219         offer.CreateDhcpOfferPacketFrom(packet)
220         
221         if self.backend.Discover(offer):
222             self.SendPacket(offer)
223         # FIXME : what if false ?
224
225
226     def HandleDhcpRequest(self, packet):
227         """Build and send DHCPACK or DHCPNACK packet in response to
228         DHCPREQUEST packet. 4 types of DHCPREQUEST exists."""
229
230         ip = packet.GetOption("request_ip_address")
231         sid = packet.GetOption("server_identifier")
232         ciaddr = packet.GetOption("ciaddr")
233         #packet.PrintHeaders()
234         #packet.PrintOptions()
235
236         if sid != [0,0,0,0] and ciaddr == [0,0,0,0] :
237             Log.Output(Log.info, "Get DHCPREQUEST_SELECTING_STATE packet")
238
239         elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip :
240             Log.Output(Log.info, "Get DHCPREQUEST_INITREBOOT_STATE packet")
241
242         elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip :
243             Log.Output(Log.info,"Get DHCPREQUEST_INITREBOOT_STATE packet")
244
245         else : Log.Output(Log.info,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented")
246
247         if self.backend.Request(packet) : packet.TransformToDhcpAckPacket()
248         else : packet.TransformToDhcpNackPacket()
249
250         self.SendPacket(packet)
251
252
253
254     # FIXME: These are not yet implemented.
255     def HandleDhcpDecline(self, packet):
256         Log.Output(Log.info, "Get DHCPDECLINE packet")
257         self.backend.Decline(packet)
258         
259     def HandleDhcpRelease(self, packet):
260         Log.Output(Log.info,"Get DHCPRELEASE packet")
261         self.backend.Release(packet)
262         
263     def HandleDhcpInform(self, packet):
264         Log.Output(Log.info, "Get DHCPINFORM packet")
265
266         if self.backend.Request(packet) :
267             packet.TransformToDhcpAckPacket()
268             # FIXME : Remove lease_time from options
269             self.SendPacket(packet)
270
271         # FIXME : what if false ?
272
273 if '__main__' == __name__:
274     options = { "server_listen_port":67,
275                 "client_listen_port":68,
276                 "listen_address":"0.0.0.0"}
277     backend = DhcpBackend('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
278     server = DhcpServer(backend, options)
279
280     while True : server.GetNextDhcpPacket()