X-Git-Url: http://xvm.mit.edu/gitweb/invirt/packages/invirt-dhcp.git/blobdiff_plain/5b5216809d7e7d0e78df31d274c2e97eb77be2c2..9007b014f45be76bf183371353068bab12b749f6:/code/dhcpserver.py diff --git a/code/dhcpserver.py b/code/dhcpserver.py new file mode 100644 index 0000000..3133643 --- /dev/null +++ b/code/dhcpserver.py @@ -0,0 +1,265 @@ +#!/usr/bin/python +import sys +sys.path.append('pydhcplib/') +import pydhcplib +import pydhcplib.dhcp_network +from pydhcplib.dhcp_packet import * +from pydhcplib.type_hw_addr import hwmac +from pydhcplib.type_ipv4 import ipv4 +from pydhcplib.type_strlist import strlist +import socket +import IN + +import event_logger +if '__main__' == __name__: + event_logger.init("stdout", 'DEBUG', {}) +from event_logger import Log + +import psycopg2 +import time +import sipb_xen_database +from sqlalchemy import create_engine + +dhcp_options = {'subnet_mask': '255.255.0.0', + 'router': '18.181.0.1', + 'domain_name_server': '18.70.0.160,18.71.0.151,18.72.0.3', + 'domain_name': 'mit.edu', + 'ip_address_lease_time': 60*60*24} + +class DhcpBackend: + def __init__(self, database=None): + if database is not None: + self.database = database + sipb_xen_database.connect(create_engine(database)) + def findNIC(self, mac): + for i in range(3): + try: + value = sipb_xen_database.NIC.get_by(mac_addr=mac) + except psycopg2.OperationalError: + time.sleep(0.5) + if i == 2: #Try twice to reconnect. + raise + #Sigh. SQLAlchemy should do this itself. + sipb_xen_database.connect(create_engine(self.database)) + else: + break + return value + def find_interface(self, packet): + chaddr = hwmac(packet.GetHardwareAddress()) + nic = self.findNIC(str(chaddr)) + if nic is None or nic.ip is None: + return ("18.181.0.60", None) + ipstr = ''.join(reversed(['%02X' % i for i in ipv4(nic.ip).list()])) + for line in open('/proc/net/route'): + parts = line.split() + if parts[1] == ipstr: + Log.Output(Log.debug, "find_interface found "+str(nic.ip)+" on "+parts[0]) + return ("18.181.0.60", parts[0]) + return ("18.181.0.60", None) + + def getParameters(self, **extra): + all_options=dict(dhcp_options) + all_options.update(extra) + options = {} + for parameter, value in all_options.iteritems(): + if value is None: + continue + option_type = DhcpOptionsTypes[DhcpOptions[parameter]] + + if option_type == "ipv4" : + # this is a single ip address + options[parameter] = map(int,value.split(".")) + elif option_type == "ipv4+" : + # this is multiple ip address + iplist = value.split(",") + opt = [] + for single in iplist : + opt.extend(ipv4(single).list()) + options[parameter] = opt + elif option_type == "32-bits" : + # This is probably a number... + digit = int(value) + options[parameter] = [digit>>24&0xFF,(digit>>16)&0xFF,(digit>>8)&0xFF,digit&0xFF] + elif option_type == "16-bits" : + digit = int(value) + options[parameter] = [(digit>>8)&0xFF,digit&0xFF] + + elif option_type == "char" : + digit = int(value) + options[parameter] = [digit&0xFF] + + elif option_type == "bool" : + if value=="False" or value=="false" or value==0 : + options[parameter] = [0] + else : options[parameter] = [1] + + elif option_type == "string" : + options[parameter] = strlist(value).list() + + else : + options[parameter] = strlist(value).list() + return options + + def Discover(self, packet): + Log.Output(Log.debug,"dhcp_backend : Discover ") + chaddr = hwmac(packet.GetHardwareAddress()) + nic = self.findNIC(str(chaddr)) + if nic is None or nic.machine is None: + return False + ip = nic.ip + if ip is None: #Deactivated? + return False + if nic.hostname and '.' in nic.hostname: + hostname = nic.hostname + elif nic.machine.name: + hostname = nic.machine.name + '.servers.csail.mit.edu' + else: + hostname = None + if ip is not None: + ip = ipv4(ip) + Log.Output(Log.debug,"dhcp_backend : Discover result = "+str(ip)) + packet_parameters = self.getParameters(host_name=hostname) + + # FIXME: Other offer parameters go here + packet_parameters["yiaddr"] = ip.list() + + packet.SetMultipleOptions(packet_parameters) + return True + return False + + def Request(self, packet): + Log.Output(Log.debug, "dhcp_backend : Request") + + discover = self.Discover(packet) + + chaddr = hwmac(packet.GetHardwareAddress()) + request = packet.GetOption("request_ip_address") + if not request: + request = packet.GetOption("ciaddr") + yiaddr = packet.GetOption("yiaddr") + + if not discover: + Log.Output(Log.info,"Unknown MAC address: "+str(chaddr)) + return False + + if yiaddr!="0.0.0.0" and yiaddr == request : + Log.Output(Log.info,"Ack ip "+str(yiaddr)+" for "+str(chaddr)) + return True + else: + Log.Output(Log.info,"Requested ip "+str(request)+" not available for "+str(chaddr)) + return False + + def Decline(self, packet): + pass + def Release(self, packet): + pass + + +class DhcpServer(pydhcplib.dhcp_network.DhcpServer): + def __init__(self, backend, options = {'client_listenport':68,'server_listenport':67}): + pydhcplib.dhcp_network.DhcpServer.__init__(self,"0.0.0.0",options["client_listen_port"],options["server_listen_port"],) + self.backend = backend + Log.Output(Log.debug, "__init__ DhcpServer") + + def SendDhcpPacketTo(self, To, packet): + (ip, intf) = self.backend.find_interface(packet) + if intf: + out_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) + out_socket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST,1) + out_socket.setsockopt(socket.SOL_SOCKET, IN.SO_BINDTODEVICE, intf) + #out_socket.bind((ip, self.listen_port)) + ret = out_socket.sendto(packet.EncodePacket(), (To,self.emit_port)) + out_socket.close() + return ret + else: + return self.dhcp_socket.sendto(packet.EncodePacket(),(To,self.emit_port)) + + def SendPacket(self, packet): + """Encode and send the packet.""" + + giaddr = packet.GetOption('giaddr') + + # in all case, if giaddr is set, send packet to relay_agent + # network address defines by giaddr + if giaddr!=[0,0,0,0] : + agent_ip = ".".join(map(str,giaddr)) + self.SendDhcpPacketTo(agent_ip,packet) + Log.Output(Log.debug, "SendPacket to agent : "+agent_ip) + + # FIXME: This shouldn't broadcast if it has an IP address to send + # it to instead. See RFC2131 part 4.1 for full details + else : + Log.Output(Log.debug, "No agent, broadcast packet.") + self.SendDhcpPacketTo("255.255.255.255",packet) + + + def HandleDhcpDiscover(self, packet): + """Build and send DHCPOFFER packet in response to DHCPDISCOVER + packet.""" + + logmsg = "Get DHCPDISCOVER packet from " + hwmac(packet.GetHardwareAddress()).str() + + Log.Output(Log.info, logmsg) + offer = DhcpPacket() + offer.CreateDhcpOfferPacketFrom(packet) + + if self.backend.Discover(offer): + self.SendPacket(offer) + # FIXME : what if false ? + + + def HandleDhcpRequest(self, packet): + """Build and send DHCPACK or DHCPNACK packet in response to + DHCPREQUEST packet. 4 types of DHCPREQUEST exists.""" + + ip = packet.GetOption("request_ip_address") + sid = packet.GetOption("server_identifier") + ciaddr = packet.GetOption("ciaddr") + #packet.PrintHeaders() + #packet.PrintOptions() + + if sid != [0,0,0,0] and ciaddr == [0,0,0,0] : + Log.Output(Log.info, "Get DHCPREQUEST_SELECTING_STATE packet") + + elif sid == [0,0,0,0] and ciaddr == [0,0,0,0] and ip : + Log.Output(Log.info, "Get DHCPREQUEST_INITREBOOT_STATE packet") + + elif sid == [0,0,0,0] and ciaddr != [0,0,0,0] and not ip : + Log.Output(Log.info,"Get DHCPREQUEST_INITREBOOT_STATE packet") + + else : Log.Output(Log.info,"Get DHCPREQUEST_UNKNOWN_STATE packet : not implemented") + + if self.backend.Request(packet) : packet.TransformToDhcpAckPacket() + else : packet.TransformToDhcpNackPacket() + + self.SendPacket(packet) + + + + # FIXME: These are not yet implemented. + def HandleDhcpDecline(self, packet): + Log.Output(Log.info, "Get DHCPDECLINE packet") + self.backend.Decline(packet) + + def HandleDhcpRelease(self, packet): + Log.Output(Log.info,"Get DHCPRELEASE packet") + self.backend.Release(packet) + + def HandleDhcpInform(self, packet): + Log.Output(Log.info, "Get DHCPINFORM packet") + + if self.backend.Request(packet) : + packet.TransformToDhcpAckPacket() + # FIXME : Remove lease_time from options + self.SendPacket(packet) + + # FIXME : what if false ? + +if '__main__' == __name__: + options = { "server_listen_port":67, + "client_listen_port":68, + "listen_address":"0.0.0.0"} + backend = DhcpBackend('postgres://sipb-xen@sipb-xen-dev/sipb_xen') + server = DhcpServer(backend, options) + + while True : server.GetNextDhcpPacket()