我正在使用用python编写的Ryu开放流量控制器开关监视我的虚拟mininet中的数据包 . 我有3个主机,我阻止从host2到host3以及从host3到host2的传输 . 其他数据包将添加到交换机流表中 . 我的问题是,在添加流后,如果它们是在交换机的流表中有规则的2个主机之间的数据包,则我的事件不会触发 . 例如,如果交换机看到从host1到host2的数据包,则它是合法的,因此将流添加到表中,但如果发送从host1到host2的另一个数据包,则不会再次通过该方法 . 我查看了Ryu指南,但是当流已经添加到交换机流表时没有找到任何关于这种情况的话 . 我该如何 grab 数据包?
提前致谢 .
这是我的代码:
import logging
import struct
from ryu.base import app_manager
from ryu.controller import mac_to_port
from ryu.controller import ofp_event
from ryu.controller.handler import MAIN_DISPATCHER
from ryu.controller.handler import set_ev_cls
from ryu.ofproto import ofproto_v1_0
from ryu.lib.mac import haddr_to_str
class SimpleSwitch(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_0.OFP_VERSION]
counterTraffic=0
def __init__(self, *args, **kwargs):
super(SimpleSwitch, self).__init__(*args, **kwargs)
self.mac_to_port = {}
def add_flow(self, datapath, in_port, dst, actions):
ofproto = datapath.ofproto
wildcards = ofproto_v1_0.OFPFW_ALL
wildcards &= ~ofproto_v1_0.OFPFW_IN_PORT
wildcards &= ~ofproto_v1_0.OFPFW_DL_DST
match = datapath.ofproto_parser.OFPMatch(
wildcards, in_port, 0, dst,
0, 0, 0, 0, 0, 0, 0, 0, 0)
mod = datapath.ofproto_parser.OFPFlowMod(
datapath=datapath, match=match, cookie=0,
command=ofproto.OFPFC_ADD, idle_timeout=0, hard_timeout=0,
priority=ofproto.OFP_DEFAULT_PRIORITY,
flags=ofproto.OFPFF_SEND_FLOW_REM, actions=actions)
datapath.send_msg(mod)
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
print("Im in main function")
msg = ev.msg
datapath = msg.datapath
ofproto = datapath.ofproto
dst, src, _eth_type = struct.unpack_from('!6s6sH', buffer(msg.data), 0)
dpid = datapath.id
self.mac_to_port.setdefault(dpid, {})
self.logger.info("packet in %s %s %s %s",
dpid, haddr_to_str(src), haddr_to_str(dst),
msg.in_port)
if (haddr_to_str(dst) == "00:00:00:00:00:01"):
print "dst"
self.counterTraffic +=1
if not ((haddr_to_str(src) == "00:00:00:00:00:02" and haddr_to_str(dst) =="00:00:00:00:00:03")or (haddr_to_str(src) == "00:00:00:00:00:03" and haddr_to_str(dst) =="00:00:00:00:00:02")):
# learn a mac address to avoid FLOOD next time.
print("after condition")
self.mac_to_port[dpid][src] = msg.in_port
if dst in self.mac_to_port[dpid]:
out_port = self.mac_to_port[dpid][dst]
else:
out_port = ofproto.OFPP_FLOOD
actions = [datapath.ofproto_parser.OFPActionOutput(out_port)]
# install a flow to avoid packet_in next time
if out_port != ofproto.OFPP_FLOOD:
self.add_flow(datapath, msg.in_port, dst, actions)
out = datapath.ofproto_parser.OFPPacketOut(
datapath=datapath, buffer_id=msg.buffer_id, in_port=msg.in_port,
actions=actions)
datapath.send_msg(out)
if (haddr_to_str(src) == "00:00:00:00:00:01"):
print "src"
self.counterTraffic +=1
print(self.counterTraffic)
@set_ev_cls(ofp_event.EventOFPPortStatus, MAIN_DISPATCHER)
def _port_status_handler(self, ev):
msg = ev.msg
reason = msg.reason
port_no = msg.desc.port_no
ofproto = msg.datapath.ofproto
if reason == ofproto.OFPPR_ADD:
self.logger.info("port added %s", port_no)
elif reason == ofproto.OFPPR_DELETE:
self.logger.info("port deleted %s", port_no)
elif reason == ofproto.OFPPR_MODIFY:
self.logger.info("port modified %s", port_no)
else:
self.logger.info("Illeagal port state %s %s", port_no, reason)
1 回答
简短的故事是你正确地解码了目标mac地址......但是,IP必须通过ARP来解析mac地址,这就是为什么你看到
ff:ff:ff:ff:ff:ff
......那些只是ryu controller中的ARP帧 .我构建了一个完整的控制器,解码到下面的IPv4层......
更新了ryu switch包解码器
你一直在解码原始
structs
,但是使用ryu Packet library更容易,而不是解压缩数据包的原始struct
. 这是我非常快速地替换_packet_in_handler()
,它只打印出源和目标mac地址,以及上层协议......现在,无论何时发送以太网数据包,您都会在mininet会话中看到这个...
ARP数据包看起来像这样......
演示
假设我将上面修改过的代码(包括源代码的其他部分)保存为
ne_question.py
.ff:ff:ff:ff:ff:ff
. 顺便说一句,如果你将wget
更改为h2 wget h1
,一切正常......