如何让Scapy支持组VXLAN报文 | SDNLAB

作者简介：刘敬一，盛科网络SDN交换机产品线测试主管

1.下载scapy2.3.2
Scapy的是一个强大的交互式数据包处理程序（使用python编写）。它能够伪造或者解码大量的网络协议数据包，能够发送、捕捉、匹配请求和回复包等等。戳这里下载Scapy
2.解压缩

ljyfree@ubuntu:~$ unzip scapy-2.3.2.zip

1	ljyfree@ubuntu:~$ unzip scapy-2.3.2.zip

3.修改/scapy/all.py

ljyfree@ubuntu:~/scapy-2.3.2/scapy$ pwd
/home/centec/scapy-2.3.2/scapy
ljyfree@ubuntu:~/scapy-2.3.2/scapy$ vi all.py
添加一行
from contrib.all import *

ljyfree@ubuntu:~/scapy-2.3.2/scapy$ pwd

/home/centec/scapy-2.3.2/scapy

ljyfree@ubuntu:~/scapy-2.3.2/scapy$ vi all.py

添加一行

from contrib.all import *

4.查看vxlan.py
此时/scapy/contrib/下，应该已经有人提交过vxlan.py

ljyfree@ubuntu:~/scapy-2.3.2/scapy$ cd contrib/
ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$ 
ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$ more vxlan.py 
# RFC 7348 - Virtual eXtensible Local Area Network (VXLAN):
# A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
# http://tools.ietf.org/html/rfc7348

# scapy.contrib.description = VXLAN
# scapy.contrib.status = loads

from scapy.packet import Packet, bind_layers
from scapy.layers.l2 import Ether
from scapy.layers.inet import UDP
from scapy.fields import FlagsField, XByteField, ThreeBytesField

_VXLAN_FLAGS = ['R' for i in range(0, 24)] + ['R', 'R', 'R', 'I', 'R', 'R', 'R', 'R', 'R'] 


class VXLAN(Packet):
    name = "VXLAN"
    fields_desc = [FlagsField("flags", 0x08000000, 32, _VXLAN_FLAGS),
                   ThreeBytesField("vni", 0),
                   XByteField("reserved", 0x00)]

    def mysummary(self):
        return self.sprintf("VXLAN (vni=%VXLAN.vni%)")

bind_layers(UDP, VXLAN, dport=4789)
bind_layers(VXLAN, Ether)
ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$

ljyfree@ubuntu:~/scapy-2.3.2/scapy$ cd contrib/

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$ more vxlan.py

# RFC 7348 - Virtual eXtensible Local Area Network (VXLAN):

# A Framework for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks

# http://tools.ietf.org/html/rfc7348

# scapy.contrib.description = VXLAN

# scapy.contrib.status = loads

from scapy.packet import Packet, bind_layers

from scapy.layers.l2 import Ether

from scapy.layers.inet import UDP

from scapy.fields import FlagsField, XByteField, ThreeBytesField

_VXLAN_FLAGS = ['R' for i in range(0, 24)] + ['R', 'R', 'R', 'I', 'R', 'R', 'R', 'R', 'R']

class VXLAN(Packet):

name = "VXLAN"

fields_desc = [FlagsField("flags", 0x08000000, 32, _VXLAN_FLAGS),

ThreeBytesField("vni", 0),

XByteField("reserved", 0x00)]

def mysummary(self):

return self.sprintf("VXLAN (vni=%VXLAN.vni%)")

bind_layers(UDP, VXLAN, dport=4789)

bind_layers(VXLAN, Ether)

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$

5.在scapy/contrib里面添加all.py
结合scapy/all.py，可以看到这里的all.py用来加载contrib/下面的各个协议定义，尤其要包含vxlan

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$ more all.py

from scapy.config import conf
from scapy.error import log_loading
import logging
log = logging.getLogger("scapy.loading")

def _import_star(m):
    mod = __import__(m, globals(), locals())
    for k,v in mod.__dict__.iteritems():
        globals()[k] = v

_contrib_modules_ = ["bgp","igmp","igmpv3","ldp","mpls","ospf","ripng","rsvp", "vxlan"]

for _l in _contrib_modules_:
    log_loading.debug("Loading module %s" % _l)
    try:
        _import_star(_l)
    except Exception,e:
        log.warning("can't import module %s: %s" % (_l,e))

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$ more all.py

from scapy.config import conf

from scapy.error import log_loading

import logging

log = logging.getLogger("scapy.loading")

def _import_star(m):

mod = __import__(m, globals(), locals())

for k,v in mod.__dict__.iteritems():

globals()[k] = v

_contrib_modules_ = ["bgp","igmp","igmpv3","ldp","mpls","ospf","ripng","rsvp", "vxlan"]

for _l in _contrib_modules_:

log_loading.debug("Loading module %s" % _l)

try:

_import_star(_l)

except Exception,e:

log.warning("can't import module %s: %s" % (_l,e))

ljyfree@ubuntu:~/scapy-2.3.2/scapy/contrib$

6.安装

ljyfree@ubuntu:~/scapy-2.3.2$ sudo python setup.py install
running install
running build
running build_py
running build_scripts
running install_lib
...
running install_scripts
copying build/scripts-2.7/UTscapy -> /usr/local/bin
copying build/scripts-2.7/scapy -> /usr/local/bin
changing mode of /usr/local/bin/UTscapy to 775
changing mode of /usr/local/bin/scapy to 775
running install_data
creating /usr/local/share/man/man1
copying doc/scapy.1.gz -> /usr/local/share/man/man1
running install_egg_info
Writing /usr/local/lib/python2.7/dist-packages/scapy-2.3.2.egg-info
ljyfree@ubuntu:~/scapy-2.3.2$

ljyfree@ubuntu:~/scapy-2.3.2$ sudo python setup.py install

running install

running build

running build_py

running build_scripts

running install_lib

...

running install_scripts

copying build/scripts-2.7/UTscapy -> /usr/local/bin

copying build/scripts-2.7/scapy -> /usr/local/bin

changing mode of /usr/local/bin/UTscapy to 775

changing mode of /usr/local/bin/scapy to 775

running install_data

creating /usr/local/share/man/man1

copying doc/scapy.1.gz -> /usr/local/share/man/man1

running install_egg_info

Writing /usr/local/lib/python2.7/dist-packages/scapy-2.3.2.egg-info

ljyfree@ubuntu:~/scapy-2.3.2$

7.验证

ljyfree@ubuntu:~/scapy-2.3.2$ scapy
INFO: Can't import python gnuplot wrapper . Won't be able to plot.
INFO: Can't import PyX. Won't be able to use psdump() or pdfdump().
WARNING: No route found for IPv6 destination :: (no default route?)
WARNING: can't import module igmp: name 'IP' is not defined
IGMPv3  is still under development - Nov 2010
WARNING: can't import module igmpv3: name 'IP' is not defined
WARNING: can't import module ospf: name 'IP6Field' is not defined
Welcome to Scapy (2.3.2)
>>> 
>>> 
>>> p = Ether()/IP()/UDP()/VXLAN()
>>> p.show()
###[ Ethernet ]###
  dst= ff:ff:ff:ff:ff:ff
  src= 00:00:00:00:00:00
  type= 0x800
###[ IP ]###
     version= 4
     ihl= None
     tos= 0x0
     len= None
     id= 1
     flags= 
     frag= 0
     ttl= 64
     proto= udp
     chksum= None
     src= 127.0.0.1
     dst= 127.0.0.1
     \options\
###[ UDP ]###
        sport= domain
        dport= 4789
        len= None
        chksum= None
###[ VXLAN ]###
           flags= I
           vni= 0
           reserved= 0x0
>>>

ljyfree@ubuntu:~/scapy-2.3.2$ scapy

INFO: Can't import python gnuplot wrapper . Won't be able to plot.

INFO: Can't import PyX. Won't be able to use psdump() or pdfdump().

WARNING: No route found for IPv6 destination :: (no default route?)

WARNING: can't import module igmp: name 'IP' is not defined

IGMPv3 is still under development - Nov 2010

WARNING: can't import module igmpv3: name 'IP' is not defined

WARNING: can't import module ospf: name 'IP6Field' is not defined

Welcome to Scapy (2.3.2)

>>>

>>> p = Ether()/IP()/UDP()/VXLAN()

>>> p.show()

###[ Ethernet ]###

dst= ff:ff:ff:ff:ff:ff

src= 00:00:00:00:00:00

type= 0x800

###[ IP ]###

version= 4

ihl= None

tos= 0x0

len= None

id= 1

flags=

frag= 0

ttl= 64

proto= udp

chksum= None

src= 127.0.0.1

dst= 127.0.0.1

\options\

###[ UDP ]###

sport= domain

dport= 4789

len= None

chksum= None

###[ VXLAN ]###

flags= I

vni= 0

reserved= 0x0

>>>

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