How to send an IP packet with given hex payload in Python?

yegorov-p picture yegorov-p · Nov 30, 2010 · Viewed 12k times · Source

I have sniffed an IGMP packet and now I would like to send it with the help of python. Is there any way to just send packet like

0x0000   01 00 5E 00 43 67 00 02-B3 C8 7F 44 81 00 00 DE   ..^.Cg..іИD?..Ю
0x0010   08 00 46 00 00 20 00 01-00 00 01 02 36 4C C0 A8   ..F.. ......6LАЁ
0x0020   00 7B EA 00 43 67 94 04-00 00 16 00 BC 97 EA 00   .{к.Cg”.....ј—к.
0x0030   43 67                                             Cg

without any packet generators like impacket?

UPD Ok, I tried to use raw sockets, like that:

dst = '234.0.67.103'

# Open a raw socket.
s = socket.socket(socket.AF_INET, socket.SOCK_RAW,2)

res=''

temp='01 00 5E 00 43 67 00 02 B3 C8 7F 44 81 00 00 DE 08 00 46 00 00 20 00 01 00 00 01 02 36 4C C0 A8 00 7B EA 00 43 67 94 04 00 00 16 00 BC 97 EA 00 43 67'
for i in temp.split(' '):
    res+=chr(int(i, 16))
print res
s.sendto(res, (dst, 0))

Everything is fine except one little thing... If I sniff that packet, it looks like that:

0x0000   01 00 5E 00 43 67 00 02-B3 C8 7F 44 08 00 45 00   ..^.Cg..іИD..E.
0x0010   00 46 07 06 00 00 01 02-C4 25 C0 A8 00 7B EA 00   .F......Д%АЁ.{к.
0x0020   43 67 01 00 5E 00 43 67-00 02 B3 C8 7F 44 81 00   Cg..^.Cg..іИDЃ.
0x0030   00 DE 08 00 46 00 00 20-00 01 00 00 01 02 36 4C   .Ю..F.. ......6L
0x0040   C0 A8 00 7B EA 00 43 67-94 04 00 00 16 00 BC 97   АЁ.{к.Cg”.....ј—
0x0050   EA 00 43 67                                       к.Cg

As you can see, for some reason python ignores my headers and creates its own. How can I fix it?

Answer

denis4inet picture denis4inet · Mar 6, 2014

Due to Unix Network Programming (3th ed):

sockfd = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_RAW)
# inform os about that program are compose ip header
sockfd.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL, True)