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dhcps.py
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from ryu.base import app_manager
from ryu.controller import ofp_event
from ryu.controller.handler import CONFIG_DISPATCHER, MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.lib import addrconv, hub
from ryu.lib.packet import dhcp, ethernet
from ryu.lib.packet import ipv4, packet, udp, arp
from ryu.ofproto import ofproto_v1_3
from ryu.topology import event
from ryu.topology import switches
import threading
import struct
import random
import time
class DHCPResponder(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
_EVENTS = [
event.EventHostAdd,
event.EventHostDelete
]
def __init__(self, *args, **kwargs):
super(DHCPResponder, self).__init__(*args, **kwargs)
self.name = 'dhcp'
self.release_time = 30
self.hw_addr = '0a:e4:1c:d1:3e:44'
self.dhcp_server = '10.0.0.1'
self.netmask = '255.0.0.0'
self.dns = '8.8.8.8'
self.bin_dns = addrconv.ipv4.text_to_bin(self.dns)
self.hostname = 'dhcp'
self.bin_netmask = addrconv.ipv4.text_to_bin(self.netmask)
self.bin_server = addrconv.ipv4.text_to_bin(self.dhcp_server)
self.ip_pool = {} #记录每个mac对应的ip，以及最近一次更新的时间
self.ip_addr = '10.0.0.'
self.usable_id = [i for i in range(2, 254)]
self.mac_port = {} #记录每个mac对应的交换机端口以及交换机编号
@set_ev_cls(ofp_event.EventOFPSwitchFeatures, CONFIG_DISPATCHER)
def switch_features_handler(self, ev):
datapath = ev.msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
# install table-miss flow entry
#
# We specify NO BUFFER to max_len of the output action due to
# OVS bug. At this moment, if we specify a lesser number, e.g.,
# 128, OVS will send Packet-In with invalid buffer_id and
# truncated packet data. In that case, we cannot output packets
# correctly. The bug has been fixed in OVS v2.1.0.
match = parser.OFPMatch()
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER,
ofproto.OFPCML_NO_BUFFER)]
self.add_flow(datapath, 0, match, actions)
def add_flow(self, datapath, priority, match, actions, buffer_id=None):
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
inst = [parser.OFPInstructionActions(ofproto.OFPIT_APPLY_ACTIONS,
actions)]
if buffer_id:
mod = parser.OFPFlowMod(datapath=datapath, buffer_id=buffer_id,
priority=priority, match=match,
instructions=inst)
else:
mod = parser.OFPFlowMod(datapath=datapath, priority=priority,
match=match, instructions=inst)
datapath.send_msg(mod)
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
pkt = packet.Packet(data=msg.data)
pkt_udp = pkt.get_protocol(udp.udp)
port = msg.match['in_port']
pkt_arp = pkt.get_protocol(arp.arp)
if pkt_arp:
self.arp_handle(ev)
if pkt_udp is None or udp.udp.get_packet_type(pkt_udp.src_port, pkt_udp.dst_port) != dhcp.dhcp:
return
if msg.msg_len < msg.total_len:
# print("packet trucate %d of %d bytes" % (msg.msg_len, msg.total_len))
#通过截断包可以知道对应主机对应端口
actions = [parser.OFPActionOutput(ofproto.OFPP_CONTROLLER)]
out = parser.OFPPacketOut(datapath=datapath,
buffer_id=msg.buffer_id,
in_port=ofproto.OFPP_CONTROLLER,
actions=actions
)
self.mac_port[pkt.get_protocol(ethernet.ethernet).src] = [datapath.id, port]
datapath.send_msg(out)
return
pkt = packet.Packet(data=msg.data)
pkt_dhcp = pkt.get_protocol(dhcp.dhcp)
smac = pkt.get_protocol(ethernet.ethernet).src
port = self.mac_port[smac][1]
if pkt_dhcp:
self._handle_dhcp(datapath, port, pkt)
def assemble_ack(self, pkt):
#self.semaphore.acquire()
#self.semaphore.release()
req_eth = pkt.get_protocol(ethernet.ethernet)
req_ipv4 = pkt.get_protocol(ipv4.ipv4)
req_udp = pkt.get_protocol(udp.udp)
req = pkt.get_protocol(dhcp.dhcp)
req.options.option_list.remove(
next(opt for opt in req.options.option_list if opt.tag == 53))
req.options.option_list.insert(
0, dhcp.option(tag=1, value=self.bin_netmask))
req.options.option_list.insert(
0, dhcp.option(tag=3, value=self.bin_server))
req.options.option_list.insert(
0, dhcp.option(tag=6, value=self.bin_dns))
# disc.options.option_list.insert(
# 0, dhcp.option(tag=12, value=self.hostname))
req.options.option_list.insert(
0, dhcp.option(tag=51, value=struct.pack('!I', self.release_time)))
req.options.option_list.insert(
0, dhcp.option(tag=53, value=struct.pack('!B', 5)))
# disc.options.option_list.insert(
# 0, dhcp.option(tag=54, value=self.hostname))
req.options.option_list.insert(
0, dhcp.option(tag=58, value=struct.pack('!I', self.release_time // 2)))
req.options.option_list.insert(
0, dhcp.option(tag=59, value=struct.pack('!I', self.release_time * 7 // 8)))
if req_eth.src not in self.ip_pool:
return
# print(req_eth.src,end=" ")
# print(self.ip_pool[req_eth.src][2], time.perf_counter())
self.ip_pool[req_eth.src][1] = time.perf_counter()
ack_pkt = packet.Packet()
ack_pkt.add_protocol(ethernet.ethernet(
ethertype=req_eth.ethertype, dst=req_eth.src, src=self.hw_addr))
ack_pkt.add_protocol(
ipv4.ipv4(dst=req_ipv4.dst, src=self.dhcp_server, proto=req_ipv4.proto))
ack_pkt.add_protocol(udp.udp(src_port=67, dst_port=68))
ack_pkt.add_protocol(dhcp.dhcp(op=2, chaddr=req_eth.src,
siaddr=self.dhcp_server,
boot_file=req.boot_file,
yiaddr=self.ip_pool[req_eth.src][0],
xid=req.xid,
options=req.options))
self.host_check()
# self.logger.info("ASSEMBLED ACK: %s" % ack_pkt)
return ack_pkt
def assemble_offer(self, port, pkt):
#self.semaphore.acquire()
disc_eth = pkt.get_protocol(ethernet.ethernet)
disc_ipv4 = pkt.get_protocol(ipv4.ipv4)
disc_udp = pkt.get_protocol(udp.udp)
disc = pkt.get_protocol(dhcp.dhcp)
try:
disc.options.option_list.remove(
next(opt for opt in disc.options.option_list if opt.tag == 50))
except:
pass
disc.options.option_list.remove(
next(opt for opt in disc.options.option_list if opt.tag == 55))
disc.options.option_list.remove(
next(opt for opt in disc.options.option_list if opt.tag == 53))
disc.options.option_list.remove(
next(opt for opt in disc.options.option_list if opt.tag == 12))
disc.options.option_list.insert(
0, dhcp.option(tag=1, value=self.bin_netmask))
disc.options.option_list.insert(
0, dhcp.option(tag=3, value=self.bin_server))
disc.options.option_list.insert(
0, dhcp.option(tag=6, value=self.bin_dns))
# disc.options.option_list.insert(
# 0, dhcp.option(tag=12, value=self.hostname))
disc.options.option_list.insert(
0, dhcp.option(tag=51, value=struct.pack('!I', self.release_time)))
disc.options.option_list.insert(
0, dhcp.option(tag=53, value=struct.pack('!B', 2)))
# disc.options.option_list.insert(
# 0, dhcp.option(tag=54, value=self.hostname))
disc.options.option_list.insert(
0, dhcp.option(tag=58, value=struct.pack('!I', self.release_time // 2)))
disc.options.option_list.insert(
0, dhcp.option(tag=59, value=struct.pack('!I', self.release_time * 7 // 8)))
if disc_eth.src not in self.ip_pool:
nid = random.choice(self.usable_id)
nip = self.ip_addr + str(nid)
#print("new host in,mac:" + disc_eth.src + ",ip:" + nip)
self.usable_id.remove(nid)
self.ip_pool[disc_eth.src] = [nip, time.perf_counter()]
else:
self.ip_pool[disc_eth.src][1] = time.perf_counter()
#print(disc_eth.src, str(self.mac_port[disc_eth.src][1])+":"+str(self.mac_port[disc_eth.src][1]))
h = switches.Host(disc_eth.src, str(self.mac_port[disc_eth.src][0])+":"+str(self.mac_port[disc_eth.src][1]))
h.ipv4.append(self.ip_pool[disc_eth.src][0])
self.send_event_to_observers(event.EventHostAdd(h))
nip = self.ip_pool[disc_eth.src][0]
offer_pkt = packet.Packet()
offer_pkt.add_protocol(ethernet.ethernet(
ethertype=disc_eth.ethertype, dst=disc_eth.src, src=self.hw_addr))
offer_pkt.add_protocol(
ipv4.ipv4(dst=disc_ipv4.dst, src=self.dhcp_server, proto=disc_ipv4.proto))
offer_pkt.add_protocol(udp.udp(src_port=67, dst_port=68))
offer_pkt.add_protocol(dhcp.dhcp(op=2, chaddr=disc_eth.src,
siaddr=self.dhcp_server,
boot_file=disc.boot_file,
yiaddr=nip,
xid=disc.xid,
options=disc.options))
return offer_pkt
def get_state(self, pkt_dhcp):
"""
:param pkt_dhcp: 解析后的dhcp报文
:return: dhcp报文的消息类型
"""
dhcp_state = ord(
[opt for opt in pkt_dhcp.options.option_list if opt.tag == 53][0].value)
if dhcp_state == 1:
state = 'DHCPDISCOVER'
elif dhcp_state == 2:
state = 'DHCPOFFER'
elif dhcp_state == 3:
state = 'DHCPREQUEST'
elif dhcp_state == 4:
state = 'DHCPDECLINE'
elif dhcp_state == 5:
state = 'DHCPACK'
elif dhcp_state == 6:
state = 'DHCPNAK'
elif dhcp_state == 7:
state = 'DHCPRELEASE'
elif dhcp_state == 8:
state = 'DHCPINFORM'
return state
def _handle_dhcp(self, datapath, port, pkt):
"""
:param datapath:交换机标识
:param port: 交换机端口
:param pkt: DHCP报文
根据DHCP的消息类型发送不同类型的包
"""
pkt_dhcp = pkt.get_protocol(dhcp.dhcp)
dhcp_state = self.get_state(pkt_dhcp)
if dhcp_state == 'DHCPDISCOVER':
self._send_packet(datapath, port, self.assemble_offer(port, pkt))
elif dhcp_state == 'DHCPREQUEST':
self._send_packet(datapath, port, self.assemble_ack(pkt))
else:
return
def _send_packet(self, datapath, port, pkt):
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
if pkt is None:
return
pkt.serialize()
# print("packet-out %s" % (pkt,))
data = pkt.data
actions = [parser.OFPActionOutput(port=port)]
out = parser.OFPPacketOut(datapath=datapath,
buffer_id=ofproto.OFP_NO_BUFFER,
in_port=ofproto.OFPP_CONTROLLER,
actions=actions,
data=data)
datapath.send_msg(out)
# 定期检查超时未能更新的主机，删除之
def host_check(self):
# while self.is_active:
# self.check_event.clear()
for m in list(self.ip_pool.keys()):
if time.perf_counter() - self.ip_pool[m][1] > 30:
#print(time.perf_counter(), self.ip_pool[m][2])
id = int(self.ip_pool[m][0].split('.')[-1])
#print(m, str(self.mac_port[m][0])+":"+str(self.mac_port[m][1]))
h = switches.Host(m, str(self.mac_port[m][0])+":"+str(self.mac_port[m][1]))
h.ipv4.append(self.ip_pool[m][0])
self.send_event_to_observers(event.EventHostDelete(h))
del self.ip_pool[m]
del self.mac_port[m]
self.usable_id.append(id)
# self.check_event.wait(30)
def arp_handle(self, ev):
"""
获取到源主机发送的ARP请求包，伪装成目的主机，给源主机发送ARP响应
:param ev:
:return:
"""
msg = ev.msg
print("#############################################")
datapath = msg.datapath
dpid = datapath.id
port = msg.match['in_port']
pkt = packet.Packet(data=msg.data)
pkt_eth = pkt.get_protocol(ethernet.ethernet)
# if not pkt_eth:
# print("packet-in: %s" % (pkt_eth,))
# return
# else:
# dst_mac = pkt_eth.dst
# eth_type = pkt_eth.ethertype
# This 'if condition' is for learning the ip and mac addresses of hosts as well as .
pkt_arp = pkt.get_protocol(arp.arp)
if not pkt_arp:
return
else:
print("datapath id: " + str(dpid))
print("port: " + str(port))
print("pkt_eth.dst: " + str(pkt_eth.dst))
print("pkt_eth.src: " + str(pkt_eth.src))
print("pkt_arp: " + str(pkt_arp))
print("pkt_arp:src_ip: " + str(pkt_arp.src_ip))
print("pkt_arp:dst_ip: " + str(pkt_arp.dst_ip))
print("pkt_arp:src_mac: " + str(pkt_arp.src_mac))
print("pkt_arp:dst_mac: " + str(pkt_arp.dst_mac))
# Destination and source ip address
dst_ip = pkt_arp.dst_ip
src_ip = pkt_arp.src_ip
# Destination and source mac address (HW address)
dst_mac = pkt_arp.dst_mac
src_mac = pkt_arp.src_mac
target_mac = self.get_mac_by_ip(dst_ip) # 源主机希望获得的目的主机的mac
self._handle_arp(datapath, port, pkt_eth, pkt_arp, target_mac, dst_ip)
def get_mac_by_ip(self, target_ip):
for item in self.ip_pool:
ip = self.ip_pool[item][0]
if ip == target_ip:
return item
def _handle_arp(self, datapath, port, pkt_ethernet, pkt_arp, target_hw_addr, target_ip_addr):
"""
构造一个ARP响应包并发送给源主机
:return:
"""
if pkt_arp.opcode != arp.ARP_REQUEST:
return
pkt = packet.Packet()
pkt.add_protocol(ethernet.ethernet(ethertype=pkt_ethernet.ethertype,
dst=pkt_ethernet.src,
src=target_hw_addr))
pkt.add_protocol(arp.arp(opcode=arp.ARP_REPLY,
src_mac=target_hw_addr,
src_ip=target_ip_addr,
dst_mac=pkt_arp.src_mac,
dst_ip=pkt_arp.src_ip))
self._send_packet(datapath, port, pkt)
def _send_packet(self, datapath, port, pkt):
ofproto = datapath.ofproto
parser = datapath.ofproto_parser
pkt.serialize()
data = pkt.data
actions = [parser.OFPActionOutput(port=port)]
out = parser.OFPPacketOut(datapath=datapath,
buffer_id=ofproto.OFP_NO_BUFFER,
in_port=ofproto.OFPP_CONTROLLER,
actions=actions,
data=data)
datapath.send_msg(out)