Python: python-dpkt : send an ICMP echo packet w/ python-dpkt

I am a newbie to python script.

just follow instructions.

http://jon.oberheide.org/blog/2008/08/25/dpkt-tutorial-1-icmp-echo/

Many thx XD

OS : BackTrack Linux 5 ( installed python-dpkt )

1. send an ICMP echo packet w/ python-dpkt

This tutorial is very useful for me to study python.

root@bt:~# less /usr/share/pyshared/dpkt/icmp.py

imcp.py

class ICMP(dpkt.Packet):    __hdr__ = (        ('type', 'B', 8),        ('code', 'B', 0),        ('sum', 'H', 0)        )    class Echo(dpkt.Packet):        __hdr__ = (('id', 'H', 0), ('seq', 'H', 0))

>>> dir(dpkt.icmp.ICMP.Echo) ['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__getitem__', '__hash__', '__hdr__', '__hdr_defaults__', '__hdr_fields__', '__hdr_fmt__', '__hdr_len__', '__init__', '__len__', '__metaclass__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__slots__', '__str__', '__subclasshook__', '__weakref__', 'data', 'id', 'pack', 'pack_hdr', 'seq', 'unpack']

create echo payload

>>> import dpkt >>> echo = dpkt.icmp.ICMP.Echo() >>> print `echo` Echo()

Echo payloads:

id : 16bit int ( ‘H’) : default 0   ('id', 'H', 0)

seq : 16bit int (‘H’) : default 0   ('seq', 'H', 0)

create id n’ seq # w/ random.randint

>>> import random >>> random.randint(0,0xffff) 23065

create id , seq attributes

>>> import random >>> echo.id = random.randint(0,0xffff) >>> echo.seq = random.randint(0,0xffff) >>> print `echo` Echo(id=46957, seq=51509)

create data attributes

>>> echo.data = 'hello world' >>> >>> print `echo` Echo(id=46957, seq=51509, data='hello world')

create ICMP payload n’ assign its attributes

>>> icmp = dpkt.icmp.ICMP() >>> icmp.type = dpkt.icmp.ICMP_ECHO

link Echo payload to data ICMP attribute

>>> icmp.data = echo >>> >>> print `echo` Echo(id=46957, seq=51509, data='hello world') >>> print `icmp.data` Echo(id=46957, seq=51509, data='hello world') >>> print `icmp` ICMP(data=Echo(id=46957, seq=51509, data='hello world')) >>> import binascii >>> print binascii.hexlify(str(icmp)) 0800e58db76dc93568656c6c6f20776f726c64 >>> print str(icmp) 卷mﾉ5hello world

Next create a socket for ICMP.

>>> s = socket.socket(socket.AF_INET, socket.SOCK_RAW, dpkt.ip.IP_PROTO_ICMP) >>> s.connect(('192.168.10.11',1))

http://docs.python.org/dev/library/socket.html ( ‘bout python socket )

send an ICMP echo to 192.168.10.11

>>> s.send(str(icmp)) 19

Captured on 192.168.10.11

# tshark -i eth2 icmp 102.144392 192.168.10.20 -> 192.168.10.11 ICMP Echo (ping) request 102.144420 192.168.10.11 -> 192.168.10.20 ICMP Echo (ping) reply

root@bt:~/my_works# cat ping.py #!/usr/bin/env python import dpkt,socket,random echo = dpkt.icmp.ICMP.Echo() echo.id = random.randint(0, 0xffff) echo.seq = random.randint(0, 0xffff) echo.data = 'hello world' icmp = dpkt.icmp.ICMP() icmp.type = dpkt.icmp.ICMP_ECHO icmp.data = echo s = socket.socket(socket.AF_INET, socket.SOCK_RAW, dpkt.ip.IP_PROTO_ICMP) s.connect(('192.168.10.11', 1)) sent = s.send(str(icmp)) print 'sent %d bytes' % sent root@bt:~/my_works# python ping.py sent 19 bytes