Use correct dhcp options, and use SO_BINDTODEVICE to send out the right device
[invirt/packages/invirt-dhcp.git] / 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 import socket
11 import IN
12
13 import event_logger
14 if '__main__' == __name__:
15     event_logger.init("stdout", 'DEBUG', {})
16 from event_logger import Log
17
18 import psycopg2
19 import time
20 import sipb_xen_database
21 from sqlalchemy import create_engine
22
23 dhcp_options = {'subnet_mask': '255.255.0.0',
24                 'router': '18.181.0.1',
25                 'domain_name_server': '18.70.0.160,18.71.0.151,18.72.0.3',
26                 'domain_name': 'mit.edu',
27                 'ip_address_lease_time': 60*60*24}
28
29 class DhcpBackend:
30     def __init__(self, database=None):
31         if database is not None:
32             self.database = database
33             sipb_xen_database.connect(create_engine(database))
34     def findNIC(self, mac):
35         for i in range(3):
36             try:
37                 value = sipb_xen_database.NIC.get_by(mac_addr=mac)
38             except psycopg2.OperationalError:
39                 time.sleep(0.5)
40                 if i == 2:  #Try twice to reconnect.
41                     raise
42                 #Sigh.  SQLAlchemy should do this itself.
43                 sipb_xen_database.connect(create_engine(self.database))
44             else:
45                 break
46         return value
47     def find_interface(self, packet):
48         chaddr = hwmac(packet.GetHardwareAddress())
49         nic = self.findNIC(str(chaddr))
50         if nic is None or nic.ip is None:
51             return ("18.181.0.60", None)
52         ipstr = ''.join(reversed(['%02X' % i for i in ipv4(nic.ip).list()]))
53         for line in open('/proc/net/route'):
54             parts = line.split()
55             if parts[1] == ipstr:
56                 Log.Output(Log.debug, "find_interface found "+str(nic.ip)+" on "+parts[0])
57                 return ("18.181.0.60", parts[0])
58         return ("18.181.0.60", None)
59                             
60     def getParameters(self, **extra):
61         all_options=dict(dhcp_options)
62         all_options.update(extra)
63         options = {}
64         for parameter, value in all_options.iteritems():
65             if value is None:
66                 continue
67             option_type = DhcpOptionsTypes[DhcpOptions[parameter]]
68
69             if option_type == "ipv4" :
70                 # this is a single ip address
71                 options[parameter] = map(int,value.split("."))
72             elif option_type == "ipv4+" :
73                 # this is multiple ip address
74                 iplist = value.split(",")
75                 opt = []
76                 for single in iplist :
77                     opt.extend(ipv4(single).list())
78                 options[parameter] = opt
79             elif option_type == "32-bits" :
80                 # This is probably a number...
81                 digit = int(value)
82                 options[parameter] = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF]
83             elif option_type == "16-bits" :
84                 digit = int(value)
85                 options[parameter] = [(digit>>8)&0xFF,digit&0xFF]
86
87             elif option_type == "char" :
88                 digit = int(value)
89                 options[parameter] = [digit&0xFF]
90
91             elif option_type == "bool" :
92                 if value=="False" or value=="false" or value==0 :
93                     options[parameter] = [0]
94                 else : options[parameter] = [1]
95                     
96             elif option_type == "string" :
97                 options[parameter] = strlist(value).list()
98                 
99             else :
100                 options[parameter] = strlist(value).list()
101         return options
102
103     def Discover(self, packet):
104         Log.Output(Log.debug,"dhcp_backend : Discover ")
105         chaddr = hwmac(packet.GetHardwareAddress())
106         nic = self.findNIC(str(chaddr))
107         if nic is None:
108             return False
109         ip = nic.ip
110         if ip is None:  #Deactivated?
111             return False
112         hostname = nic.hostname
113         if hostname is not None:
114             hostname += ".servers.csail.mit.edu"
115         if ip is not None:
116             ip = ipv4(ip)
117             Log.Output(Log.debug,"dhcp_backend : Discover result = "+str(ip))
118             packet_parameters = self.getParameters(host_name=hostname)
119
120             # FIXME: Other offer parameters go here
121             packet_parameters["yiaddr"] = ip.list()
122             
123             packet.SetMultipleOptions(packet_parameters)
124             return True
125         return False
126         
127     def Request(self, packet):
128         Log.Output(Log.debug, "dhcp_backend : Request")
129         
130         discover = self.Discover(packet)
131         
132         chaddr = hwmac(packet.GetHardwareAddress())
133         request = packet.GetOption("request_ip_address")
134         if not request:
135             request = packet.GetOption("ciaddr")
136         yiaddr = packet.GetOption("yiaddr")
137
138         if not discover:
139             Log.Output(Log.info,"Unknown MAC address: "+str(chaddr))
140             return False
141         
142         if yiaddr!="0.0.0.0" and yiaddr == request :
143             Log.Output(Log.info,"Ack ip "+str(yiaddr)+" for "+str(chaddr))
144             return True
145         else:
146             Log.Output(Log.info,"Requested ip "+str(request)+" not available for "+str(chaddr))
147         return False
148
149     def Decline(self, packet):
150         pass
151     def Release(self, packet):
152         pass
153     
154
155 class DhcpServer(pydhcplib.dhcp_network.DhcpServer):
156     def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}):
157         pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],)
158         self.backend = backend
159         Log.Output(Log.debug, "__init__ DhcpServer")
160
161     def SendDhcpPacketTo(self, To, packet):
162         (ip, intf) = self.backend.find_interface(packet)
163         if intf:
164             out_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
165             out_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST,1)
166             out_socket.setsockopt(socket.SOL_SOCKET, IN.SO_BINDTODEVICE, intf)
167             #out_socket.bind((ip, self.listen_port))
168             ret = out_socket.sendto(packet.EncodePacket(), (To,self.emit_port))
169             out_socket.close()
170             return ret
171         else:
172             return self.dhcp_socket.sendto(packet.EncodePacket(),(To,self.emit_port))
173
174     def SendPacket(self, packet):
175         """Encode and send the packet."""
176         
177         giaddr = packet.GetOption('giaddr')
178
179         # in all case, if giaddr is set, send packet to relay_agent
180         # network address defines by giaddr
181         if giaddr!=[0,0,0,0] :
182             agent_ip = ".".join(map(str,giaddr))
183             self.SendDhcpPacketTo(agent_ip,packet)
184             Log.Output(Log.debug, "SendPacket to agent : "+agent_ip)
185
186         # FIXME: This shouldn't broadcast if it has an IP address to send
187         # it to instead. See RFC2131 part 4.1 for full details
188         else :
189             Log.Output(Log.debug, "No agent, broadcast packet.")
190             self.SendDhcpPacketTo("255.255.255.255",packet)
191             
192
193     def HandleDhcpDiscover(self, packet):
194         """Build and send DHCPOFFER packet in response to DHCPDISCOVER
195         packet."""
196
197         logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str()
198
199         Log.Output(Log.info, logmsg)
200         offer = DhcpPacket()
201         offer.CreateDhcpOfferPacketFrom(packet)
202         
203         if self.backend.Discover(offer):
204             self.SendPacket(offer)
205         # FIXME : what if false ?
206
207
208     def HandleDhcpRequest(self, packet):
209         """Build and send DHCPACK or DHCPNACK packet in response to
210         DHCPREQUEST packet. 4 types of DHCPREQUEST exists."""
211
212         ip = packet.GetOption("request_ip_address")
213         sid = packet.GetOption("server_identifier")
214         ciaddr = packet.GetOption("ciaddr")
215         #packet.PrintHeaders()
216         #packet.PrintOptions()
217
218         if sid != [0,0,0,0] and ciaddr == [0,0,0,0] :
219             Log.Output(Log.info, "Get DHCPREQUEST_SELECTING_STATE packet")
220
221         elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip :
222             Log.Output(Log.info, "Get DHCPREQUEST_INITREBOOT_STATE packet")
223
224         elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip :
225             Log.Output(Log.info,"Get DHCPREQUEST_INITREBOOT_STATE packet")
226
227         else : Log.Output(Log.info,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented")
228
229         if self.backend.Request(packet) : packet.TransformToDhcpAckPacket()
230         else : packet.TransformToDhcpNackPacket()
231
232         self.SendPacket(packet)
233
234
235
236     # FIXME: These are not yet implemented.
237     def HandleDhcpDecline(self, packet):
238         Log.Output(Log.info, "Get DHCPDECLINE packet")
239         self.backend.Decline(packet)
240         
241     def HandleDhcpRelease(self, packet):
242         Log.Output(Log.info,"Get DHCPRELEASE packet")
243         self.backend.Release(packet)
244         
245     def HandleDhcpInform(self, packet):
246         Log.Output(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     backend = DhcpBackend('postgres://sipb-xen@sipb-xen-dev/sipb_xen')
260     server = DhcpServer(backend, options)
261
262     while True : server.GetNextDhcpPacket()