def _respond_dhcp(self, datapath, port, pool,
pkt_ethernet, pkt_vlan, pkt_ip, pkt_udp, pkt_dhcp):
# DHCP message type code
options = dict()
for option in pkt_dhcp.options.option_list:
options[option.tag] = option.value
src = pkt_dhcp.chaddr
# RESPONSE MSG
pkt = packet.Packet()
pkt.add_protocol(ethernet.ethernet(ethertype=pkt_ethernet.ethertype,
dst=pkt_ethernet.src,
src='00:00:00:00:00:00'))
if pkt_vlan:
pkt.add_protocol(vlan.vlan(cfi=pkt_vlan.cfi,
ethertype=pkt_vlan.ethertype,
pcp=pkt_vlan.pcp,
vid=pkt_vlan.vid))
pkt.add_protocol(ipv4.ipv4(src=pkt_ip.dst, dst=pkt_ip.src, proto=in_proto.IPPROTO_UDP))
pkt.add_protocol(udp.udp(src_port=pkt_udp.dst_port, dst_port=pkt_udp.src_port))
# DISCOVER MSG
dhcp_msg_type = ord(options[dhcp.DHCP_MESSAGE_TYPE_OPT])
if dhcp_msg_type == dhcp.DHCP_DISCOVER:
msg_type = dhcp.DHCP_OFFER
if src in self.leases:
offer = self.leases[src]
del self.leases[src]
self.offers[src] = offer
else:
offer = self.offers.get(src)
if offer is None:
if len(pool) == 0:
LOG.error("Out of IP addresses")
msg_type = dhcp.DHCP_NAK
offer = pool[0]
if dhcp.DHCP_REQUESTED_IP_ADDR_OPT in options:
wanted_ip = IPAddr(addrconv.ipv4.bin_to_text(options[dhcp.DHCP_REQUESTED_IP_ADDR_OPT].value))
if wanted_ip in pool:
offer = wanted_ip
pool.remove(offer)
self.offers[src] = offer
wanted_opts = list()
if dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT in options:
fmt = "s" * len(options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
wanted_opt_set = struct.unpack(fmt, options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
for i in wanted_opt_set:
wanted_opts.append(ord(i))
option_list = list()
option_list.append(dhcp.option(dhcp.DHCP_MESSAGE_TYPE_OPT, chr(msg_type), length=1))
if msg_type is not dhcp.DHCP_NAK:
if dhcp.DHCP_SUBNET_MASK_OPT in wanted_opts:
option_list.append(dhcp.option(dhcp.DHCP_SUBNET_MASK_OPT,
addrconv.ipv4.text_to_bin(self.subnet.toStr()),
length=4))
if dhcp.DHCP_GATEWAY_ADDR_OPT in wanted_opts and self.router_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_GATEWAY_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.router_addr.toStr()),
length=4))
if dhcp.DHCP_DNS_SERVER_ADDR_OPT in wanted_opts and self.dns_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_DNS_SERVER_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.dns_addr.toStr()),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_IP_ADDR_LEASE_TIME_OPT,
chr(self.lease_time),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_RENEWAL_TIME_OPT, chr(self.lease_time / 2), length=4))
option_list.append(dhcp.option(dhcp.DHCP_REBINDING_TIME_OPT, chr(self.lease_time * 7 / 8), length=4))
resp_options = dhcp.options(option_list=option_list)
pkt.add_protocol(dhcp.dhcp(op=self._MSG_TYPE_BOOT_REPLY, chaddr=pkt_dhcp.chaddr, options=resp_options,
xid=pkt_dhcp.xid, ciaddr=pkt_dhcp.ciaddr, yiaddr=offer.toStr(),
siaddr=self.ip_addr.toStr(), giaddr='0.0.0.0', sname='', boot_file=''))
# REQUEST MSG
if dhcp_msg_type == dhcp.DHCP_REQUEST:
msg_type = dhcp.DHCP_ACK
if dhcp.DHCP_REQUESTED_IP_ADDR_OPT not in options:
return
wanted_ip = IPAddr(addrconv.ipv4.bin_to_text(options[dhcp.DHCP_REQUESTED_IP_ADDR_OPT]))
got_ip = None
if src in self.leases:
if wanted_ip != self.leases[src]:
pool.append(self.leases[src])
del self.leases[src]
else:
got_ip = self.leases[src]
if got_ip is None:
if src in self.offers:
if wanted_ip != self.offers[src]:
pool.append(self.offers[src])
del self.offers[src]
else:
got_ip = self.offers[src]
if got_ip is None:
if wanted_ip in pool:
pool.remove(wanted_ip)
got_ip = wanted_ip
if got_ip is None:
LOG.warn("%s asked for un-offered %s", src, wanted_ip.toStr())
msg_type = dhcp.DHCP_NAK
wanted_opts = list()
if dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT in options:
fmt = "s" * len(options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
wanted_opt_set = struct.unpack(fmt, options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
for i in wanted_opt_set:
wanted_opts.append(ord(i))
# DHCP options tag code
option_list = list()
option_list.append(dhcp.option(dhcp.DHCP_MESSAGE_TYPE_OPT, chr(msg_type), length=1))
if msg_type is not dhcp.DHCP_NAK:
if dhcp.DHCP_SUBNET_MASK_OPT in wanted_opts:
option_list.append(dhcp.option(dhcp.DHCP_SUBNET_MASK_OPT,
addrconv.ipv4.text_to_bin(self.subnet.toStr()),
length=4))
if dhcp.DHCP_GATEWAY_ADDR_OPT in wanted_opts and self.router_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_GATEWAY_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.router_addr.toStr()),
length=4))
if dhcp.DHCP_DNS_SERVER_ADDR_OPT in wanted_opts and self.dns_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_DNS_SERVER_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.dns_addr.toStr()),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_IP_ADDR_LEASE_TIME_OPT,
chr(self.lease_time),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_RENEWAL_TIME_OPT, chr(self.lease_time / 2), length=4))
option_list.append(dhcp.option(dhcp.DHCP_REBINDING_TIME_OPT, chr(self.lease_time * 7 / 8), length=4))
resp_options = dhcp.options(option_list=option_list)
pkt.add_protocol(dhcp.dhcp(op=self._MSG_TYPE_BOOT_REPLY, chaddr=pkt_dhcp.chaddr, options=resp_options,
xid=pkt_dhcp.xid, ciaddr=pkt_dhcp.ciaddr, yiaddr=wanted_ip.toStr(),
siaddr=self.ip_addr.toStr(), giaddr='0.0.0.0', sname='', boot_file=''))
# RELEASE MSG
if dhcp_msg_type == dhcp.DHCP_RELEASE:
if self.leases.get(src).toStr() != pkt_dhcp.ciaddr:
LOG.warn("%s tried to release unleased %s" % (src, pkt_dhcp.ciaddr))
return
del self.leases[src]
pool.append(pkt_dhcp.ciaddr)
LOG.info("%s released %s" % (src, pkt_dhcp.ciaddr))
self._send_dhcp_reply(datapath, port, pkt)
return True
class Dhcpd(app_manager.RyuApp):
_MSG_TYPE_BOOT_REPLY = 2
_MSG_TYPE_BOOT_REQ = 1
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
def __init__(self, ip_address="192.168.0.254", router_address=(), dns_address=(), pool=None, subnet=None,
install_flow=True):
super(Dhcpd, self).__init__()
def fix_addr(addr, backup):
if addr is None:
return None
if addr is ():
return IPAddr(backup)
return IPAddr(addr)
self._install_flow = install_flow
self.ip_addr = IPAddr(ip_address)
self.router_addr = fix_addr(router_address, ip_address)
self.dns_addr = fix_addr(dns_address, self.router_addr)
if pool is None:
self.pool = [IPAddr("192.168.0." + str(x)) for x in range(100, 199)]
self.subnet = IPAddr(subnet or "255.255.255.0")
else:
self.pool = pool
self.subnet = subnet
if hasattr(pool, 'subnet_mask'):
self.subnet = pool.subnet_mask
if self.subnet is None:
raise RuntimeError("You must specify a subnet mask or use a pool with a subnet hint")
self.lease_time = 180
# TODO: Actually make them expire :)
self.offers = {} # Eth -> IP we offered
self.leases = {} # Eth -> IP we leased
if self.ip_addr in self.pool:
LOG.debug("Removing my own IP (%s) from address pool", self.ip_addr)
self.pool.remove(self.ip_addr)
# core.openflow.addListeners(self)
def _get_pool(self):
return self.pool
def add_dhcp_flow(self, datapath):
ofproto = datapath.ofproto
match = datapath.ofproto_parser.OFPMatch(eth_type=ether.ETH_TYPE_IP,
ip_proto=inet.IPPROTO_UDP,
udp_src=68,
udp_dst=67)
actions = [datapath.ofproto_parser.OFPActionOutput(datapath.ofproto_parser.OFPP_CONTROLLER)]
instructions = [datapath.ofproto_parser.OFPInstructionActions(
ofproto.OFPIT_APPLY_ACTIONS, actions)]
mod = datapath.ofproto_parser.OFPFlowMod(
datapath=datapath, cookie=0, cookie_mask=0, table_id=0,
command=ofproto.OFPFC_ADD, idle_timeout=0, hard_timeout=0,
priority=1, buffer_id=ofproto.OFP_NO_BUFFER,
flags=0, match=match, instructions=instructions)
datapath.send_msg(mod)
@log_helpers.log_method_call
def _send_dhcp_reply(self, datapath, port, pkt):
ofp = datapath.ofproto
ofpp = datapath.ofproto_parser
pkt.serialize()
data = pkt.data
actions = [ofpp.OFPActionOutput(port=port)]
out = ofpp.OFPPacketOut(datapath=datapath,
buffer_id=ofp.OFP_NO_BUFFER,
in_port=ofp.OFPP_CONTROLLER,
actions=actions,
data=data)
datapath.send_msg(out)
@handler.set_ev_cls(ofp_event.EventOFPPacketIn, handler.MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
"""Check a packet-in message.
Build and output an dhcp reply if a packet-in message is
an dhcp packet.
"""
msg = ev.msg
LOG.debug("packet-in msg %s", msg)
datapath = msg.datapath
port = msg.match['in_port']
# NOTE: Ryu packet library can raise various exceptions on a corrupted packet.
try:
pkt = packet.Packet(msg.data)
except Exception as e:
LOG.debug("Unparsable packet: got exception %s", e)
return
LOG.debug("packet-in dpid %(dpid)s in_port %(port)s pkt %(pkt)s",
{'dpid': dpid_lib.dpid_to_str(datapath.id),
'port': port, 'pkt': pkt})
pkt_ethernet = pkt.get_protocol(ethernet.ethernet)
if not pkt_ethernet:
LOG.debug("drop non-ethernet packet")
return
pkt_vlan = pkt.get_protocol(vlan.vlan)
pkt_ip = pkt.get_protocol(ipv4.ipv4)
if pkt_ip is None:
return
pkt_udp = pkt.get_protocol(udp.udp)
if pkt_udp is None:
return
pkt_dhcp = pkt.get_protocol(dhcp.dhcp)
if pkt_dhcp is None:
LOG.debug("drop non-dhcp packet")
return
pool = self._get_pool()
if pool is None:
return
self._respond_dhcp(datapath, port, pool, pkt_ethernet, pkt_vlan, pkt_ip, pkt_udp, pkt_dhcp)
def _respond_dhcp(self, datapath, port, pool,
pkt_ethernet, pkt_vlan, pkt_ip, pkt_udp, pkt_dhcp):
# DHCP message type code
options = dict()
for option in pkt_dhcp.options.option_list:
options[option.tag] = option.value
src = pkt_dhcp.chaddr
# RESPONSE MSG
pkt = packet.Packet()
pkt.add_protocol(ethernet.ethernet(ethertype=pkt_ethernet.ethertype,
dst=pkt_ethernet.src,
src='00:00:00:00:00:00'))
if pkt_vlan:
pkt.add_protocol(vlan.vlan(cfi=pkt_vlan.cfi,
ethertype=pkt_vlan.ethertype,
pcp=pkt_vlan.pcp,
vid=pkt_vlan.vid))
pkt.add_protocol(ipv4.ipv4(src=pkt_ip.dst, dst=pkt_ip.src, proto=in_proto.IPPROTO_UDP))
pkt.add_protocol(udp.udp(src_port=pkt_udp.dst_port, dst_port=pkt_udp.src_port))
# DISCOVER MSG
dhcp_msg_type = ord(options[dhcp.DHCP_MESSAGE_TYPE_OPT])
if dhcp_msg_type == dhcp.DHCP_DISCOVER:
msg_type = dhcp.DHCP_OFFER
if src in self.leases:
offer = self.leases[src]
del self.leases[src]
self.offers[src] = offer
else:
offer = self.offers.get(src)
if offer is None:
if len(pool) == 0:
LOG.error("Out of IP addresses")
msg_type = dhcp.DHCP_NAK
offer = pool[0]
if dhcp.DHCP_REQUESTED_IP_ADDR_OPT in options:
wanted_ip = IPAddr(addrconv.ipv4.bin_to_text(options[dhcp.DHCP_REQUESTED_IP_ADDR_OPT].value))
if wanted_ip in pool:
offer = wanted_ip
pool.remove(offer)
self.offers[src] = offer
wanted_opts = list()
if dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT in options:
fmt = "s" * len(options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
wanted_opt_set = struct.unpack(fmt, options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
for i in wanted_opt_set:
wanted_opts.append(ord(i))
option_list = list()
option_list.append(dhcp.option(dhcp.DHCP_MESSAGE_TYPE_OPT, chr(msg_type), length=1))
if msg_type is not dhcp.DHCP_NAK:
if dhcp.DHCP_SUBNET_MASK_OPT in wanted_opts:
option_list.append(dhcp.option(dhcp.DHCP_SUBNET_MASK_OPT,
addrconv.ipv4.text_to_bin(self.subnet.toStr()),
length=4))
if dhcp.DHCP_GATEWAY_ADDR_OPT in wanted_opts and self.router_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_GATEWAY_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.router_addr.toStr()),
length=4))
if dhcp.DHCP_DNS_SERVER_ADDR_OPT in wanted_opts and self.dns_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_DNS_SERVER_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.dns_addr.toStr()),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_IP_ADDR_LEASE_TIME_OPT,
chr(self.lease_time),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_RENEWAL_TIME_OPT, chr(self.lease_time / 2), length=4))
option_list.append(dhcp.option(dhcp.DHCP_REBINDING_TIME_OPT, chr(self.lease_time * 7 / 8), length=4))
resp_options = dhcp.options(option_list=option_list)
pkt.add_protocol(dhcp.dhcp(op=self._MSG_TYPE_BOOT_REPLY, chaddr=pkt_dhcp.chaddr, options=resp_options,
xid=pkt_dhcp.xid, ciaddr=pkt_dhcp.ciaddr, yiaddr=offer.toStr(),
siaddr=self.ip_addr.toStr(), giaddr='0.0.0.0', sname='', boot_file=''))
# REQUEST MSG
if dhcp_msg_type == dhcp.DHCP_REQUEST:
msg_type = dhcp.DHCP_ACK
if dhcp.DHCP_REQUESTED_IP_ADDR_OPT not in options:
return
wanted_ip = IPAddr(addrconv.ipv4.bin_to_text(options[dhcp.DHCP_REQUESTED_IP_ADDR_OPT]))
got_ip = None
if src in self.leases:
if wanted_ip != self.leases[src]:
pool.append(self.leases[src])
del self.leases[src]
else:
got_ip = self.leases[src]
if got_ip is None:
if src in self.offers:
if wanted_ip != self.offers[src]:
pool.append(self.offers[src])
del self.offers[src]
else:
got_ip = self.offers[src]
if got_ip is None:
if wanted_ip in pool:
pool.remove(wanted_ip)
got_ip = wanted_ip
if got_ip is None:
LOG.warn("%s asked for un-offered %s", src, wanted_ip.toStr())
msg_type = dhcp.DHCP_NAK
wanted_opts = list()
if dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT in options:
fmt = "s" * len(options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
wanted_opt_set = struct.unpack(fmt, options[dhcp.DHCP_PARAMETER_REQUEST_LIST_OPT])
for i in wanted_opt_set:
wanted_opts.append(ord(i))
# DHCP options tag code
option_list = list()
option_list.append(dhcp.option(dhcp.DHCP_MESSAGE_TYPE_OPT, chr(msg_type), length=1))
if msg_type is not dhcp.DHCP_NAK:
if dhcp.DHCP_SUBNET_MASK_OPT in wanted_opts:
option_list.append(dhcp.option(dhcp.DHCP_SUBNET_MASK_OPT,
addrconv.ipv4.text_to_bin(self.subnet.toStr()),
length=4))
if dhcp.DHCP_GATEWAY_ADDR_OPT in wanted_opts and self.router_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_GATEWAY_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.router_addr.toStr()),
length=4))
if dhcp.DHCP_DNS_SERVER_ADDR_OPT in wanted_opts and self.dns_addr is not None:
option_list.append(dhcp.option(dhcp.DHCP_DNS_SERVER_ADDR_OPT,
addrconv.ipv4.text_to_bin(self.dns_addr.toStr()),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_IP_ADDR_LEASE_TIME_OPT,
chr(self.lease_time),
length=4))
option_list.append(dhcp.option(dhcp.DHCP_RENEWAL_TIME_OPT, chr(self.lease_time / 2), length=4))
option_list.append(dhcp.option(dhcp.DHCP_REBINDING_TIME_OPT, chr(self.lease_time * 7 / 8), length=4))
resp_options = dhcp.options(option_list=option_list)
pkt.add_protocol(dhcp.dhcp(op=self._MSG_TYPE_BOOT_REPLY, chaddr=pkt_dhcp.chaddr, options=resp_options,
xid=pkt_dhcp.xid, ciaddr=pkt_dhcp.ciaddr, yiaddr=wanted_ip.toStr(),
siaddr=self.ip_addr.toStr(), giaddr='0.0.0.0', sname='', boot_file=''))
# RELEASE MSG
if dhcp_msg_type == dhcp.DHCP_RELEASE:
if self.leases.get(src).toStr() != pkt_dhcp.ciaddr:
LOG.warn("%s tried to release unleased %s" % (src, pkt_dhcp.ciaddr))
return
del self.leases[src]
pool.append(pkt_dhcp.ciaddr)
LOG.info("%s released %s" % (src, pkt_dhcp.ciaddr))
self._send_dhcp_reply(datapath, port, pkt)
return True
